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My dad died on April 6, and I took some time off. Below, I write about how he helped set me on this path. But first, an update on the persistent snow drought, along with a few stories I’ve been reading and some aerial snowscapes from recent flights.

Late-season storms brought much-needed moisture to parts of the West, but they didn’t come close to erasing the deficit. The snow drought continues to make headlines due to its intensity and implications.

A recent federal update shared some staggering lowlights:

• Arizona, Colorado, Idaho, Nevada, New Mexico, Oregon, Utah, and Wyoming all recorded record-low snow water equivalent on April 1 (since SNOTEL monitoring began in the 1980s). California logged its second-lowest value.

• Peak snowpack across Western states averaged 21–34 days earlier than normal, with some basins recording even larger anomalies. For example, the Upper Pecos watershed in New Mexico reached its maximum 55 days earlier than normal, while the South Platte in Colorado crested 40 days earlier than normal.

The graphic below from the National Integrated Drought Information System shows how much earlier the meltout began in each Western state.

Here’s the latest basin-level view of snow water equivalent in the West. Not good!

(One caveat: these basin maps can mislead at the very start and end of the season, when the snowpack is normally thin and a single storm can skew the percentages.)

I’m always on the hunt for a good snow graphic, and I recently found a new source: Penn State’s seasonal snowfall maps.

The two images below, based on data from NOAA’s National Operational Hydrologic Remote Sensing Center, illustrate snowfall so far this season (starting October 1). The top map shows the percent of average (2008 to present); the bottom one depicts the percentile. Either way, it’s been a dreadful snow season across much of the West.

In California, recent storms halted the freefall in the snowpack and caused the blue line below to bounce, but the statewide level was just 18% of normal on April 21.

This water year in Colorado has been a real outlier. The scatterplot below from the Colorado Climate Center shows average temperature on the vertical axis and precipitation on the horizontal axis for October through March. The star marks the current season, which has been exceptionally toasty. A few other water years have been drier, but none have come close to the warmth we’ve seen.

It’s not just Colorado. The NOAA map below shows that temperatures in October through March were the warmest since 1895 across a broad swath of the West.

Snowpack in the news: a reading list

The epic snow drought has caused journalists to flood the zone and produce a blizzard of articles about the meager snowpack’s impacts. Here are a few recent stories worth your time:

• Facing Drought and Low Snowpack, Rio Grande States Expect a ‘Challenging’ Year. Martha Pskowski, Inside Climate News, 4/20/26.

• The West’s snow drought meant record dryness — but also record flooding. Anna Marija Helt, High Country News, 4/14/26.

• Mental health stressors peak in Colorado mountain communities as the winter-that-wasn’t melts into offseason. Jason Blevins, The Colorado Sun, 4/13/26.

• Oregon ski resorts adapt to shrinking snowpack amid rough season. Joni Auden Land, Oregon Public Broadcasting, 4/12/26.

• Why scientists still use a milk scale and antique aluminum tubes to track Colorado’s record-low snowpack. Sam Brasch, Colorado Public Radio, 4/6/26.

• Record low Colorado mountain snow won’t bode well for water in the drought-stricken US West. Mead Gruver and Brittany Peterson, Associated Press, 4/1/26.

• ‘On a whole other level’: rapid snow melt-off in American west stuns scientists. Gabrielle Canon, The Guardian, 4/1/26.

• No snow. No water. Restrictions grow across West as drought fears rise. Trevor Hughes, USA Today, 3/30/26.

• Across the West, Record Heat Is Colliding With a Snow Drought. Mira Rojanasakul, Scott Dance, and Sachi Kitajima Mulkey, The New York Times, 3/21/26.

This may be the season when “snow drought” finally entered the public’s lexicon, joining such terms as “atmospheric river” and “bomb cyclone” that were once confined to weather nerds.

Earlier this season, I’ll admit that I felt a little territorial as my precious microbeat—the West’s snowpack—started attracting coverage from major news outlets. But I’ve gotten over myself. This is exactly what should happen when conditions get this bad. If anything, it’s encouraging: the story is finally breaking through, and it couldn’t matter more for the region’s future.

Remembering my dad—and the Yiddish Alps

My dad, Paul Tobin, died April 6 at age 91 after a long struggle with dementia.

In many ways, we said goodbye to him years ago. His passing brings sadness, but also relief that his ordeal is over. Our relationship was complicated, yet we loved each other deeply.

I owe my writing career largely to my late mom, Phyllis, a prolific reader who worked as an editor in Manhattan and did more than anyone to teach me how to express myself with words. But my dad—who I never saw read a single book—helped steer me to become a reporter fascinated with the weather.

My dad was no intellectual, but his blue-collar mind devoured journalism. WCBS and WINS news radio were the soundtrack to his life—and my childhood. The television was frequently tuned to the local or national news. And our home on Long Island was strewn with newspapers. We got The New York Times and Newsday delivered, and my dad would bring home the New York Post and Daily News tabloids that he’d picked up while working in Manhattan and Brooklyn at Dubrow’s Cafeteria, the family business.

My dad was especially attuned to the weather, which shaped his mercurial moods and fueled a steady stream of colorful commentary. Years later, when I was a newspaper reporter in Tucson, I’d sometimes write about the weather—rain is front-page news there—and it came naturally to me. Today, when I feel that anxious anticipation before a snowstorm, I carry forward his excitement at watching big flakes fall outside the window and betting on whether school would be canceled.

Long Island wasn’t an especially snowy place, but every so often we got walloped by a nor’easter. I’ll never forget riding on my dad’s back as we piloted a primitive Flexible Flyer down Sled Hill near our home in Great Neck. It wasn’t the Rockies, but that hill felt steep. Although Long Island lacks mountains, it owes much of its shape to the terminal moraines of a massive ice sheet that bulldozed southward just a blink ago in geologic time, leaving behind hills of glacial debris.

My dad never even came close to skiing, but he drove us a few times to The Concord Resort, an aging Borscht Belt resort in the Catskills. That’s where I made my first turns on a bunny hill in the 1970s.

I didn’t exactly shred the gnar in the Yiddish Alps, where many Jews from the New York area went to vacation. But those tiny slopes instilled a passion for skiing that I’m still chasing a half-century later. I’m forever grateful to my dad (and mom) for introducing me to a sport they didn’t pursue themselves—and, in their own ways, helping steer me toward a life in journalism.

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In the dark humor of Wall Street, a “dead cat bounce” is a brief, deceptive resurgence in prices after a market crash.

Apologies to the cat lovers, but if you drop a dead feline from high enough, it’ll rebound. This “sucker rally,” as it’s also known, doesn’t negate the precipitous drop.

That same pattern is now playing out in the mountains of the American West. The high country is getting a burst of snowfall on April 1—a key milestone for the region’s frozen reservoir, which often peaks around that date, though the timing varies by basin.

But this late-season storminess is too little, too late. It won’t rescue a lost winter that has featured record highs for temperatures and historic lows for the snowpack.

In a more typical season, I might be shredding powder on this April 1. Sadly, Purgatory—my home mountain—shut down early on Sunday, as have some other Western ski areas.

The map below paints a bleak portrait of the region’s snowpack as of March 31 (these graphics lag by a day). An already thin snow cover shriveled due to the recent off-the-charts heat waves, leaving most of the region at just a fraction of normal snow water equivalent—the measure of the snowpack’s water content.

The chart below shows Colorado’s dismal snowpack—and why experts have struggled to find superlatives to describe it. The gray band marks the record highs and lows for the statewide snowpack since 1987. The colored lines trace individual seasons over nearly four decades. The plunging black line represents the current season—an extreme outlier at just 22% of the long-term median for April 1.

Snowfall this week may cause that black line to bounce—just like the hapless cat—but it won’t rewrite the story of this brutal season.

Colorado is far from alone in recording exceptionally low snow levels. This morning, I poured a strong cup of coffee and gathered data on 10 other Western states to create the graphics below.

This chart shows each state’s snowpack as a percentage of the April 1 median (1991-2020).

And this map shows the percentile for each state’s April 1 snowpack, with eight states at 0—the lowest on record—and Washington leading the way at the 5th percentile.

In hindsight, maybe I should have had an Irish coffee.

Midpoint in the water year

April 1 marks the midway point in the water year, which began October 1, so it’s a good time to assess how the first half has played out.

Over the past six months, precipitation has been below normal in much of the West—one key driver of the current snow drought—but some areas were above average.

The second map shows that the first half of the 2025-2026 water year was much warmer than average in virtually the entire West, with the red shading indicating major departures from normal. Many Western states saw their warmest winter on record.

When I looked at how the weekly U.S. Drought Monitor has changed over the past six months, I expected to see worsening conditions across the West. After all, we’re being saturated by news coverage of the snow drought.

Yet the maps below show that the most widely used drought measure has actually improved in some parts of the West during this water year. This may seem counterintuitive, but as noted above, precipitation has been above normal in some locations—it’s just fallen as rain rather than snow. Recall, too, that waves of warm atmospheric rivers struck the West Coast at the end of 2025, easing drought in states such as California and Washington while they triggered flooding.

Even so, drought remains widespread in the West, and the scant snowpack is crimping the water supply in many locations. Utilities are already announcing water restrictions due to the snow drought.

The lack of snow is also raising fears of an intense wildfire season in a region where large blazes are a risk even in average years. The map below, released today, shows what areas have above-normal potential for significant wildfires in June.

Rather than skiing, I’ve been busy raking pine needles and cones around my home in a beautiful but flammable ponderosa pine forest near Durango.

Talking snowpack in the Chihuahuan Desert

Last week, while baking in the Chihuahuan Desert in Texas, I was reminded of the far-reaching importance of the snowpack.

I was in El Paso for a training workshop for journalists interested in the Rio Grande, sponsored by The Water Desk, the initiative at the University of Colorado Boulder that I co-direct.

It was nearly 100 degrees, there wasn’t a drop of surface water in sight, and our group was visiting the world’s largest inland desalination plant, which removes salts from brackish groundwater to make it potable.

Officials from El Paso Water, operator of the facility, spoke about the poor snowpack in the Rio Grande’s headwaters in southern Colorado—a mighty long drive away. The Rio Grande—part of the utility’s portfolio—depends heavily on that snowmelt, which is stored upstream from El Paso in Elephant Butte Reservoir (currently 13% full).

When surface water is scarce, El Paso Water relies more on local groundwater, both fresh and brackish. It’s also now constructing a Pure Water Center that will treat wastewater to create up to 10 million gallons per day of drinking water by 2028. Other cities in the Southwest are also exploring this technology, derided by some as “toilet to tap.”

As a water nerd, I found the tour of the desalination plant fascinating—and sobering. The reverse osmosis facility, which can produce up to 27.5 million gallons per day, requires significant energy to purify the brackish groundwater. The super-salty dregs are pumped 22 miles away for disposal in a fractured rock formation thousands of feet below the surface. All told, it costs El Paso Water around $2 per 1,000 gallons produced—roughly 13 times as expensive as surface water.

The West’s snowpack generates enormous economic value simply by storing water for later use. When that supply shrinks, the alternatives are pricey—or nonexistent. No technology can replicate what the snowpack does for free.

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I pitched this short op-ed on the snow drought to a variety of news outlets. Alas, I found no takers. But I’m glad I wrote the piece, and I’m excited to share it with snow.news readers, along with a few photos from my recent ski trip—the swan song of a sad season.

The West’s mountain snowpack has fallen to historic lows this winter amid record-breaking warmth, raising fears of strained water supplies and severe wildfires ahead.

Here in Colorado, it’s been a dreadful season for skiing—and for my skis.

Two miles above sea level, we call the lack of snow cover “low tide” and the underlying rocks “sharks.” Sometimes their fins are visible; other times they lurk just below the surface, ready to strike.

I’d hoped to get another year or two out of my aging skis, but repeated shark attacks this season gouged their bases and then damaged a metal edge beyond repair.

Like a receding ocean unmasking reefs and shoals, a thin year shows us dangers that lie beneath the surface—and how exposed we are.

When our snowpack is meager—or entirely missing—it underscores how much we depend on this seasonal accumulation of ice crystals, even during the summer and far beyond the region.

Besides supplying water for drinking and irrigation, snow sustains ecosystems, underpins the winter sports industry, and fuels local economies. It even cools the planet by reflecting sunlight.

When snow doesn’t fall—or moisture comes as rain due to warmer temperatures—it lays bare the fragility of the infrastructure we’ve built to cope with nature’s perils.

In one of Warren Buffett’s famous quips, we only learn who’s been swimming naked when the tide goes out. Just as falling markets uncover weaknesses in businesses, the shortage of snow is unveiling the West’s vulnerabilities: dire risks of drought and fire, plus the loss of an economic driver and a cherished part of our culture.

Not everyone loves snow. Human “snowbirds” migrate to avoid it, and this winter it delivered misery to parts of the East and South. But in the West, many of us need snow to survive—biologically, financially, and emotionally.

The West’s snowpack serves as a high-elevation frozen reservoir that stores water worth trillions of dollars. Colorado’s snow alone supplies 19 other states downstream, plus Mexico.

If you’re an American who likes salads in winter, you’re probably eating vegetables grown in the desert Southwest with water from the Colorado River, which is mostly snowmelt. This season’s dismal snowpack has only intensified the contentious negotiations over how to manage a river that supplies tens of millions of people but whose flows have already been reduced by warming.

In the West’s forests, scant snow cover heightens the threat of wildfires that can destroy entire neighborhoods and send noxious plumes thousands of miles downwind. A bad season for skiers and snowboarders often means the ensuing summer is good for flames and smoke.

As a 21st-century skier, I’ve learned not to be picky about snow conditions—as my skis will attest—but low-snow years harm businesses and workers tied to winter recreation.

Snow is like white gold for communities that cater to tourists who spend money at hotels, restaurants, bars, and retailers. Downhill snow sports generated about $59 billion in annual economic activity and supported an estimated 533,000 jobs nationwide, according to a 2024 report from the National Ski Areas Association.

Snow is a critical natural and economic resource, yet its value runs deeper when felt through the magic of snowflakes, the thrill of snowball fights, and the muffled beauty of a snow-covered landscape. As a skier and Coloradan, snow is part of my identity.

Sadly, this season’s snow drought is a harbinger of what’s to come in our warming climate. Numerous scientific studies have sounded the alarm about the fate of the West’s snow as temperatures rise.

The federal government’s Fifth National Climate Assessment, released in 2023, found climate change has already shrunk the region’s snowpack. Warming is leading to earlier peaks for accumulation and shorter seasons, especially at lower elevations and closer to the coast. The synthesis of research found “widespread consensus” that further warming will shift precipitation from snow to rain, reduce the snowpack, hasten melting, and reshape runoff patterns.

The West is trying to adapt to a diminished snowpack. Snowmaking has increased at ski resorts, but that requires water, energy, money—and cold enough weather. Many water providers are promoting conservation to stretch scarce supplies. Scientists are improving estimates of how the snowpack translates into streamflows.

Our technical knowledge of the snowpack is expanding, but it’s surfacing uncomfortable truths about how much of our future depends on a threatened resource long taken for granted.

In the Rockies and along the shore, low tide reveals hidden hazards. This season, snow’s absence is stress-testing our systems—and our resilience in a rapidly changing world.

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Adios, winter—we hardly knew thee.

After a historically dismal season for snow accumulation in the West, what little snowpack remains is set to dwindle amid a stunning March heat wave.

The forecast below, which depicts the departure from normal temperatures from today to Monday, shows why so many locations are expected to demolish records.

In eastern Utah and western Colorado, some locations will be close to 30 degrees above normal by week’s end, according to the NOAA weather radio I listen to in the shower.

Writing for CNN, Andrew Freedman describes the March heat wave this way:

Meteorologists are reaching for superlatives to describe an oncoming heat wave so intense and rare for this time of year that it could leave some locations shattering their all-time temperature records for April before that month has even begun.

This extreme event, made far worse by human-caused climate change, will bring summerlike temperatures during March to locations from California to Texas, northward all the way to Montana.

Heading into the heat wave, snowpack readings were bleak across much of the West, as shown in the March 16 map below.

The decline of the Sierra Nevada snowpack has been staggering. In the chart below, the plunging black line traces a sharp drop over recent weeks, with statewide snowpack now at just 42% of normal—and only 21% in the northern region.

Snow drought intensifies

Even before the heat wave, the West’s snow drought had been deepening.

“Snow drought worsened from February into early March due to record warmth, despite near-normal precipitation across much of the West,” according to a March 12 update from the National Integrated Drought Information System. “Every major river basin in the West experienced its first or second warmest winter (December, January, and February) on record.”

The map below shows snow water equivalent percentiles on March 8. This snow drought is both extreme and widespread, with stations across every Western state falling below the 30th percentile. All those dark red circles are at or below the 2nd percentile.

What’s most striking about this season is how strongly it has been shaped by high temperatures—a “warm” snow drought—rather than a lack of precipitation, or a “dry” snow drought.

While some parts of the West have been drier than average, even places with normal to above-normal precipitation have seen subpar snowpack because much of that moisture has fallen as rain. The map below shows that from December 2025 through February 2026, record-breaking heat affected much of the region.

“Worst-case weather scenario” for Vail Resorts

One way to quantify the severity of this season’s snow drought is through the financial performance of Vail Resorts (NYSE: MTN), a dominant player in the West’s snow sports industry.

On March 9, the company said it had experienced a “worst-case weather scenario,” noting that “season-to-date total skier visits were down 11.9% compared to the prior year period.”

“This has been the most challenging winter across the Rockies that we have ever experienced with the lowest snowfall levels in more than 30 years for our Colorado and Utah resorts, combined with warmer temperatures, resulting in reduced terrain throughout the quarter and into February,” CEO Rob Katz said.

I’m on spring break this week, so I just got back from a couple of days of skiing, one of which featured sub-zero windchills at Crested Butte, a Vail Resorts property with threadbare snow cover.

Now I’m packing a bathing suit and sandals for a trip to Sedona, Arizona, where the temperature will approach 100 degrees this week. Phoenix and Tucson will soar past the century mark in a winter that has shattered norms.

Below are the white-hot temperatures forecast for the Southwest tomorrow. On the last full day of winter, even the high country of the Rockies will be far above freezing while the deserts bake. You can even make out the Colorado River—a white, squiggly ribbon—through the Grand Canyon in northern Arizona.

Long-term projections for 21st-century precipitation can be all over the map, but the trend of rising temperatures is crystal clear. The warm snow drought we’re now experiencing is exactly what you’d expect more of as the climate heats up.

On Monday, a small wildfire started about five miles from my house near Durango. Crews now appear to have the one-acre blaze in check, but it’s foreboding to see a firefighting helicopter working in the middle of March and receive wildfire alerts on my Watch Duty app.

El Niño is looming

As winter closes out, it’s also time to say goodbye to La Niña and prepare for a likely El Niño.

The latest federal forecast on March 12 hoisted an El Niño Watch. The graphic below shows a high chance that this pattern (red bars) will take hold later this year.

This incarnation of El Niño looks to be a strong one, with some folks referring to it as a “Godzilla El Niño.”

Ben Noll of The Washington Post notes that the El Niño “could rival the strongest ones in history.”

These cyclical changes in sea-surface temperatures and atmospheric circulation in the tropical Pacific can have profound impacts on weather worldwide. Higher global temperatures are likely, as is less hurricane activity in the Atlantic. In the American West, El Niño tends to make the Southwest wetter and the Pacific Northwest drier than normal, but it’s by no means a sure thing.

Grim projection for Colorado River runoff

This season’s abysmal snowpack will have both local and far-reaching effects in the American West.

Inflows to Lake Powell on the Colorado River are projected to be paltry, adding even more pressure to the high-stakes, logjammed effort to devise new rules for the declining river.

Federal hydrologists are forecasting that Lake Powell will receive only 2.3 million acre-feet of water from April through July—just 36% of the 1991-2020 average. It looks like the worst year since 2002, a time I remember well because I spent months covering wildfires and eating smoke as a reporter for the Arizona Daily Star.

The chart below shows Powell’s projected elevation. The dotted horizontal line, at 3,490 feet, indicates “minimum power pool,” the level below which Glen Canyon Dam can’t pass water through its enormous turbines to generate hydropower. The green dashed line, which marks the “most probable” inflow to Powell, dips below the minimum power pool by the end of this year. The “probable minimum” inflow in red falls below it even sooner—this summer.

Powell is 25% full, and Mead is at 34% after more than two decades of warming-induced “megadrought.” These two metrics are like the Dow and S&P 500 for the Colorado River’s water supply. The bear market of the past quarter-century shows no signs of abating.

Durango ✈︎ Denver aerial photos

Before the heat wave, I took a quick work trip to Washington, D.C., offering me a chance to inspect Colorado’s troubled snowpack on a flight from Durango to Denver. It’s one of the most scenic 45-minute flights in the West in any season, assuming it’s not too cloudy.

In my previous post, I wrote about how snow can generate both joy and misery—often on the same day. One downside I didn’t cover was disruption to air travel, and the snow gods sure reminded me of that during my return on March 6, when Denver International Airport picked up 8.5 inches.

I somehow managed to perfectly time one of my rare visits to DIA this past year with the biggest snowstorm of the season.

We sat on the tarmac at Dulles for nearly two hours. My connection to Durango was cancelled. The last flight of the day to Durango was delayed by three hours, plus another hour as we waited for the plane—and then a flight attendant.

I spent nearly eight hours at DIA and made it home at 1 a.m., almost 18 hours after leaving the D.C. hotel.

It was all snow’s fault.

Drone images of Colorado mountain passes

On Saturday, heading to ski at Crested Butte and Monarch, I drove over three mountain passes in the San Juans above 10,000 feet. I used my drone to capture the low-to-nonexistent snowpack.

Flying a few hundred feet above the ground—rather than in a jet—offers a more intimate perspective on the conditions below.

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1) Drought, climate, and the deadly Sierra Nevada avalanche

Tragedies like the recent avalanche deaths of nine backcountry skiers in California instantly trigger the blame game: Who or what was responsible for this grievous loss of life?

Social media commentators wasted only milliseconds before fingering the guide company for exposing clients to perilous conditions. I’m reserving judgment until we learn all the facts. This story by The New York Times, based on the accounts of two survivors, is gripping and the best description of the disaster I’ve read.

Another line of inquiry has focused on the conditions that primed the snowpack to release with such disastrous consequences—and the role of the preceding snow drought.

“Snow drought helped set the stage for deadly California avalanche, leading to unstable conditions” was the headline of a story by the Associated Press.

“When weather is dry and clear, as it had been in the Sierra Nevada since January, snow crystals change and can become angular or round over time,” the AP article said, paraphrasing Craig Clements, a meteorology professor at San Jose State University. “If heavy new snow falls on the crystals, the layers often can’t bond and the new snow forms what is called a storm slab over a weaker layer.”

Outside magazine reported that “changing weather patterns in the Sierra Nevada are challenging some long-held safety assumptions held by ski guides and avalanche professionals,” citing a longtime avalanche safety instructor:

“The Sierras are dealing with persistent weak layers, and they didn’t used to,” says Tarah O’Connor, a veteran guide and instructor with the American Avalanche Institute. “It used to be a Colorado and sometimes Utah thing.”

Connor, 43, told Outside that the Sierra Nevada’s traditional wet, heavy snow—affectionately called “Sierra Cement”—becomes loose and powdery after it sits exposed to air and sunshine without additional snowfall. “It’s like sugar, really weak, really gnarly,” she said. When heavy amounts of snow fall onto this layer after long periods of warm, dry conditions—as they did prior to the deadly avalanche—the danger of a deadly slide ratchets up considerably.

Some journalists and researchers have asked whether climate change is making avalanches more likely.

The New York Times noted that “climate scientists are identifying a paradox about snowfall, avalanche risk and a warming climate, namely that drier, warmer winters will occur in the West — but more snow is expected to fall at higher elevations.”

“While scientists are careful not to blame climate change for any single weather event without close study, research suggests that a warming climate is increasing the overall risk of avalanches at higher elevations, as storms dump large amounts of snow that can overload and tumble down a mountain slope,” according to the story.

In 2024, researchers published a review of the scientific literature examining how climate change is affecting avalanches. Here’s an excerpt from the paper’s abstract:

The limited availability of comprehensive datasets, the potential confounding factors and the limitations of statistical approaches can make it difficult to identify trends in avalanche activity. However, available data indicate a general decrease in avalanche number, size, seasonality and active paths at low elevations, and an increase in the proportion of wet avalanches relative to dry avalanches. Increased snowfall at high elevations can lead to peaks in avalanche activity and an increase in the number of wet and slush-like avalanches. Activity patterns gradually shift from low to high elevations under continued warming.

One challenge in studying avalanches is that they manifest in many different ways. The figure below from the 2024 review illustrates eight types of avalanches, each with its own dynamics.

2) Preserving snow with blankets

NPR reported that Idaho’s Bogus Basin has covered machine-made snow with insulating blankets to prevent it from melting over the summer so it can be used the following winter.

“Last summer, temperatures in Bogus Basin were in the 70s and 80s. But when the staff uncovered the pile last October, 80 percent of the snow was still there. It was densely packed but usable. The ski area's snowmaking crews then used special tractors to spread out the snow,” according to the article.

The resort paid $120,000 for its first set of blankets—far cheaper than the $6 or $7 million it would have cost to build a new retaining pond for snowmaking.

“It is a bit of weatherproofing, to protect against a season like this season, where not only did we have lackluster natural snowfall, we actually had warm temperatures that didn’t allow for snowmaking,” Austin Smith, Bogus Basin’s innovation director, told reporter Jaime Geary.

The blankets are made by Snow Secure, a Finnish company. The video below shows how the technology was used to provide “100% snow security” for a resort in Finland that was hosting a World Cup ski race.

3) Reintroducing wolverines to Colorado

Wolverines are badass carnivores that depend on the snowpack for their survival. A member of the mustelid family—which includes weasels, martens, and otters—wolverines are about the size of a small dog, yet they punch way above their weight.

Wolverines are primarily scavengers, but on occasion, they’ve been known to take down much larger animals, such as a weakened deer struggling in deep snow. They travel easily across winter landscapes thanks to their oversized, snowshoe-like paws. Their powerful jaws and teeth allow them to crush bone and slice through frozen carcasses.

Despite their ferocious reputations, many wolverine populations been reduced to a fraction of their historic numbers due to trapping, poisoning, habitat fragmentation, and human encroachment. In 2023, wolverines in the Lower 48 were listed as threatened under the Endangered Species Act—primarily because of projected snowpack reductions due to climate change. Colorado recently released a plan to restore a small population in the state’s high country.

“It is estimated that Colorado can hold as many as 100-180 wolverines, which is likely similar to its historical capacity and represents a significant portion of the potential population size in the contiguous United States,” according to the reintroduction plan.

Wolverines rely on the snowpack for breeding: females dig maternity dens in deep, persistent spring snow, where they give birth and raise their kits. Without reliable late-season snowpack, those dens—and the next generation of wolverines—are at risk.

Tracy Ross at The Colorado Sun had an interesting story in January about the restoration plan and how state officials are trying to avoid problems that have plagued Colorado’s reintroduction of wolves.

4) Snowpack update: time is running out

The snowpack is still looking sad across nearly all of the West. With each passing day, we’re nearing median peak dates as temperatures warm and the sun climbs higher and stays longer in the sky.

The map below shows snow water equivalent on March 3. Only a handful of river basins are at 90% or greater (green), and none are at 100% or more, while many watersheds remain below 50% (red).

In California, the snowpack jumped after a series of February storms. But the black line in the March 3 chart below shows that the statewide level has declined since then. Overall, California’s snowpack stood at 60% of normal, with the northern region at just 40% and the southern region at 84%.

The two maps below, issued by the Climate Prediction Center on February 28, show the March temperature and precipitation outlooks. Across most of the West, the warmth is expected to continue, and there’s no signal for wetter-than-normal weather.

Every river basin has its own typical peak date, but in many places, April 1 is a key milestone for water managers and snow scientists. As we approach that waypoint, things ain’t looking good.

5) Our storm of the season?

It’s now a fading memory, but here in southwest Colorado, we got walloped a couple of weeks ago by a major winter storm. It delivered about two feet to the snow.news headquarters, more than three feet to Purgatory—my home mountain—and nearly five feet to Wolf Creek.

I’m starting to think this storm was the highlight of an otherwise moribund season. The dump reinforced how much fun—and hardship—snow can entail.

The map below shows that the same storm that led to the Sierra Nevada avalanche disaster also delivered deep accumulations to our neck of the woods.

Those purple areas in the Sierra Nevada and Colorado’s San Juans paint a vivid portrait of the orographic effects that mountains exert on snowfall totals. I remember one National Weather Forecaster in Grand Junction describing the curving shape of precipitation totals in the San Juans as the Fertile Crescent, an allusion to the cradle of irrigated agriculture in the Middle East (which depends in part on snowmelt).

Knowing the storm was coming a week in advance, I rearranged my schedule to take off at least part of two days to ski. When I was a solo consultant, I even inserted a powder day clause into my LLC’s operating agreement that ratcheted down the snowfall threshold required to trigger a day off in future years—a nod to the warming climate.

Sadly, this double-barreled storm arrived a little faster than I anticipated, so I missed the biggest totals at Purgatory on February 18. But the next day I enjoyed cleaning up the leftovers.

The second round of snow closed local schools, so I was treated to a sweet, memorable father-daughter powder day—a bright spot in an otherwise lousy ski season. But the drive up to the slopes was painfully slow and, at times, harrowing, even with four-wheel drive and studded snow tires.

I have an on-again, off-again relationship with the guy who plows many of the driveways in our neighborhood. I suspect he feels jilted that I sometimes preempt his work and clear the way myself with an aging gas-powered snowblower we inherited from the previous homeowners. This storm, I got skipped, so the 100-foot driveway was my duty.

It felt good to engage with the snow mano a mano, and it was gratifying to save the money I would have paid for plowing. But it was also slightly nauseating to breathe the blower’s emissions, and definitely annoying to spend an hour fixing the beast with cold hands.

I’ve thought about getting an electric snowblower, but they’re pricey, and I’m not sure how much snow removal I’ll be doing in the future. This season and last, there hasn’t been much to blow.

Last year, we added insulation to our attic, so our roof now holds snow longer because less heat escapes from the house. That’s provided a better tableau for observing snow’s metamorphosis. The photo below shows a slab ready to release—right onto the walkway to our front door.

At unpredictable moments, huge snow masses crash down from our roof, startling anyone at home. The snow instantly compresses into dense debris that is tough to dig through, serving as a chilling reminder of the daunting task facing avalanche rescuers. My back was sore for days after shoveling the detritus from the roof—another sign that snow can be a real pain.

It’s been an unsettling winter here, and technically speaking, there are only a few weeks left until spring. I can’t stop overhearing people—at the supermarket, in the hardware store, on the chairlift—talking about the shocking lack of snow and mild weather.

When the days are short, I’m used to firing up the wood-burning stove to help heat the house. But many evenings this winter it’s been superfluous. And I now have failing muscle memory for shoveling snow and skiing powder.

It was so warm this past weekend that we skipped skiing to go camping, hiking, and biking (in shorts) in northwest New Mexico in a bid to turn lemons into lemonade.

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The West has received a desperately needed jolt of fresh snow in recent days, and more flakes are in the forecast.

But the outlook for this season remains troubling across much of the region because we dug such a deep hole over the past few months, with several states and numerous monitoring stations recording their lowest snowpack levels in decades.

At the snow.news headquarters near Durango, we picked up about 11 inches from Tuesday night to Wednesday night thanks to the long-awaited pattern change. Another significant storm is set to arrive tonight.

The map below shows snowfall over the past 72 hours, with the highest totals in the Sierra Nevada—the site of an avalanche catastrophe I discuss below.

Looking ahead, here’s the National Weather Service forecast for snowfall over the next 48 hours.

The storminess has boosted the snow water equivalent—a measure of the snowpack’s water content—in many river basins in the West. But the map below shows that conditions by the end of yesterday remained far below normal across most of the region.

Here in Colorado, for example, data from this morning shows that the statewide snowpack (black line) has risen in recent days, but it’s still at a record low. With seven weeks to go until the median peak date of April 8, Colorado’s snowpack is just 61% of normal (1991-2020 median).

In Utah and Oregon, which also recently hit record lows, the situation has improved slightly. Utah’s statewide snow water equivalent is now at the 4th percentile and 64% of the long-term median. Oregon’s snowpack, which has only 35 days to go until its median peak on March 25, has edged up to the 2nd percentile and 35% of normal.

The most dramatic rebound in the region has occurred in California. The black line in the February 18 chart below shows a sharp rise after days of heavy snow, yet the statewide snowpack is only 69% of normal and 53% of the April 1 average.

The onslaught of snow offers a bit of good news for the West’s water supply, but the severe weather led to disaster in California’s Sierra Nevada, where an avalanche claimed the lives of at least eight backcountry skiers (a ninth person is presumed dead). The incident is the deadliest avalanche in modern California history, according to The Los Angeles Times.

In a 2024 post, I examined and visualized data on avalanche fatalities, using information from the Colorado Avalanche Information Center (CAIC) and Bruce Tremper’s Staying Alive in Avalanche Terrain.

Since 1950, the highest annual death toll from avalanches was 37 in 2021, according to CAIC. But in five of the years since 2015, fewer than 20 died across the country, so the loss of nine individuals in one incident is staggering.

Historically, February has been the deadliest month for avalanches. The most common activity was backcountry touring (337 deaths), followed by snowmobiling (310 deaths). As shown in the map below, California ranks eighth among Western states (including Alaska) for avalanche deaths, with Colorado’s notoriously sketchy snowpack claiming the most lives by far.

If you’re finding this useful, consider subscribing to snow.news for future updates — it’s free.

SnowSlang: P is for “penitentes”

SnowSlang is my occasional look at the language of snow. More at snowslang.com.

Snow can be a real shape-shifter. One of its most intriguing forms: the spire-like pinnacles known as penitentes.

Found in a few high-altitude locations, penitentes resemble blades of snow and derive their name from their resemblance to “penitents,” the procession of religious adherents in Spain and Latin America who wear white robes and pointed hoods during Holy Week while atoning for their sins.

Sometimes referred to as “nieves penitentes” to emphasize their association with snow (nieve in Spanish), the columns were first scientifically described by Charles Darwin during his 1835 travels in the Andes.

Darwin didn’t fully understand how penitentes form, but modern science offers a good explanation.

When the sun beats down on snowfall in the cold, dry, thin air of places like the high Andes, the snow can sublimate and convert directly from its solid phase into water vapor without first becoming a liquid. Irregularities in the snow cover cause some areas to disappear (ablate) faster than others, creating depressions amid ridges. The pattern of shadows and solar radiation causes the ridges to sharpen and the troughs to wither away, leading to a collection of spiky snow formations.

Solar radiation is the key driver, and penitentes respond by orienting themselves according to the sun’s angle. Because they’re all pointed in the same direction, they appear like a procession of natural snowmen.

As these pictures suggest, penitentes have a strange, almost otherworldly feel. In fact, scientists believe that similar structures exist on other celestial bodies in our solar system.

Europa, a satellite of Jupiter that has an icy crust on top of what’s believed to be a liquid ocean, may have penitentes up to 15 meters (49 feet) high, according to a 2018 study in Nature Geoscience. Scientists are keenly interested in exploring Europa since its liquid water could potentially harbor life, but the paper notes that “penitentes could pose a hazard to a future lander on Europa.”

Farther afield in the solar system, Pluto may also be home to penitentes, although they’d be made of methane ice rather than water. In 2015, when NASA’s New Horizons spacecraft passed by Pluto, it captured images of a spiky landscape that could have formed via the same process that plays out on Earth.

Our planet’s penitentes exist in an exceptionally harsh environment, yet they’re still able to support life. At an elevation of more than 17,000 feet, scientists found thriving communities of microbes, according to a 2019 study in Arctic, Antarctic, and Alpine Research.

“In this environment penitentes provide both water and shelter from harsh winds, high UV radiation, and thermal fluctuations, creating an oasis in an otherwise extreme landscape,” the researchers wrote.

The landscapes that support penitentes on Earth may provide analogues for conditions on other planets and moons, helping scientists understand how life may persist beyond Earth.

“Our study shows how no matter how challenging the environmental conditions, life finds a way when there is availability of liquid water,” Lara Vimercati, lead author of the study, said in a press release.

Sweet relief: powder at Telluride

To my eye, Telluride wins the prize for Colorado’s most scenic ski area. The competition is stiff—and I’m always willing to do more research—but the views from the top are tough to beat. In every direction, breathtaking mountains rim the horizon, and the glacially carved box canyon that cradles the town isn’t too shabby, either.

I had the good fortune to ski Telluride over Presidents’ Day weekend, and I hit the slopes after 13 inches fell in the prior 72 hours. It’s been a tough season for Telluride, not only because of meager snowfall but also due to a ski patroller strike that temporarily shut down the mountain.

With a roughly 40-inch base, the snow cover was still relatively thin, but I released a ton of pent-up turns and was thrilled to show my wife and daughter some of my favorite trails. Below are a few photos from the trip:

I’m excited to share this story I wrote for The Water Desk, an independent journalism initiative at the University of Colorado Boulder that I co-direct.

The American West’s snowpack is valuable for many reasons.

Snowmelt supplies much of the water flowing through the region’s streams, rivers, irrigation canals and household faucets—a vital role that has taken on new urgency this winter as much of the West struggles with scant snow cover.

Snowfall supports countless species, maintains forest health and helps keep a lid on wildfires. It even cools the planet by reflecting sunlight.

Snowflakes also underlie the region’s multi-billion-dollar winter sports industry, fueling local economies and drawing millions of participants. In warmer months, boating and fishing depend on water that was once frozen.

Snow performs all these functions, but can its worth be calculated in dollars and cents? And how is climate change affecting that value?

Like many aspects of nature, snow is easier to monetize in some domains than others. Its ecological benefits are complex, and its aesthetic qualities are subjective: some Westerners love the ice crystals, others dread them.

But in the economic realm, researchers have attempted to put a dollar figure on the region’s snow, and the numbers they’ve generated are huge.

“This stuff’s worth trillions, not billions” of dollars, said snow scientist Matthew Sturm, lead author of a widely cited 2017 paper in Water Resources Research that estimated the value of the water embedded in the West’s snowpack. “I turn on the tap in the Western states—what comes out of it is mostly snow.”

The Colorado River, which supplies drinking water to tens of millions of people and irrigates vast croplands, is primarily driven by snowmelt. The river generated an estimated $1.4 trillion in annual economic activity, according to a 2014 report commissioned by Protect the Flows, a business coalition, and conducted by Arizona State University. Adjusted only for inflation—not the region’s growth—that figure was equivalent to about $1.9 trillion in 2025, underscoring the high stakes of the ongoing, contentious negotiations over how to manage the Colorado River.

For some researchers, assigning a dollar value to snow is more than an academic exercise. In an era of tightening budgets and federal cutbacks in science, economic estimates can help justify investments in monitoring and studying snow—and highlight how much is at risk as the climate warms.

“If you want society to respond, you better talk about things that are fairly immediate, right at people’s doorsteps, and are easy to explain,” said Sturm, a professor of geophysics at the University of Alaska Fairbanks’ Geophysical Institute and the author of A Field Guide to Snow.

Or as Sturm’s paper puts it, “the ‘killer argument’ to the wider public that vigorous snow research is important would come by framing the argument in terms of money, something everyone understands.”

Peer-reviewed studies explicitly valuing the snowpack are rare, but some analyses have also calculated the sizable economic impact of snow sports. This winter, skiing and snowboarding in the West have been constrained not only by a lack of snowfall but also by record warmth that limited some resorts’ ability to make artificial snow.

A 2024 report from the National Ski Areas Association concluded that downhill snow sports generate $58.9 billion in annual economic activity in the United States and support an estimated 533,000 ski and snowboard jobs nationwide.

While the snowpack delivers tangible economic benefits—some easier to price than others—snowfall also carries real costs. Any accounting of snow’s economic impact must also reckon with the damage it causes.

Winter weather contributes to fatalities from avalanches in the mountains and from heart attacks in cities among people shoveling snow.

But those deaths pale in comparison to the toll on slick roads. Each year, 24% of weather-related vehicle crashes happen on snowy, slushy or icy pavement, and 15% occur when snow or sleet is falling, according to the Federal Highway Administration. More than 1,300 people are killed and more than 116,800 are injured each year in crashes on snowy, slushy or icy pavement, the agency reports, though not all of those incidents are weather related.

Valuing the snowpack’s water

The 2017 paper began with a phone call that Sturm made to Michael Goldstein, a professor of finance at Babson College with whom he had previously collaborated.

“Hey, what do you think snowpack’s worth?” Goldstein recalled Sturm asking.

Goldstein wasn’t a snow expert, but he told Sturm, “If we make some simplifying assumptions here, I could value it for you.”

“I just thought it was a cool question,” said Goldstein, who is also the Donald P. Babson Chair in Applied Investments at Babson.

Since its publication, the study has been cited nearly 400 times, according to Google Scholar.

Viewed through an economic lens, the snowpack’s role as a mountain water tower provided a clear value that Goldstein could quantify.

“Nature naturally stores the water for you for free. You didn’t have to build a reservoir,” Goldstein said. “If that goes away, that actually has a cost. And the cost is the replacement cost of either storing the water or getting water from a different source.”

Climate change is already having a variety of profound effects on the West’s snow, such as shrinking the snowpack season, but the study focuses on one key impact: the shift from snow to rain as temperatures rise.

Even if total precipitation remains unchanged in the decades ahead, a transition from snow to rain—and faster melting of the snowpack—means runoff will occur earlier in the year. In much of the West, however, it may be impossible to capture all that earlier water for later use because dam managers must leave enough empty space in reservoirs to reduce the risk of catastrophic flooding.

“There is not enough reservoir storage capacity over most of the West to handle this shift in maximum runoff and so most of the ‘early water’ will be passed on to the oceans,” according to a 2005 study.

To estimate the declining value of the snowpack in a warming climate, the 2017 paper made some assumptions about the transition from snow to rain—an evolution expected to be more pronounced in warmer regions such as California and Oregon than in colder locations like the Northern Rockies.

Examining a range of future trajectories spanning five to 100 years, the researchers assumed that half of current snowfall would fall as rain by the end of the scenario.

For the 50% of snow that would eventually convert to rain, some of the water could be captured by existing reservoirs. But while Lake Mead and Lake Powell on the Colorado River currently have plenty of room to spare, the authors note that “virtually every report we have found on the heavily dammed water systems of the West suggests that reservoir capacity (except when immediately following drought) is maxed out.” As a result, the paper assumes that water systems would lose two-thirds of the reduced snowmelt runoff.

“We’re losing, essentially, the storage capacity of snow—meaning in lieu of snow, we get rain,” Sturm said.

With their estimates of the amount of water lost as snow shifts to rain, the researchers could then multiply those figures by the cost of water to begin determining the decline in monetary value. The paper uses two water prices to bracket its estimates: $200 and $900 per acre-foot (an acre-foot is the volume of water needed to cover an acre of land to a depth of 12 inches, or 325,851 gallons).

In reality, Goldstein said, the price of water would rise as supplies became scarcer. But the paper holds water prices constant over time, an assumption that yields a conservative estimate of the snowpack’s value.

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Discounting the future

The price of water varies greatly across the West, so estimates of the snowpack’s value will necessarily span a broad range. But water costs aren’t the only reason it’s challenging to pin down the snowpack’s monetary worth.

Another challenge the paper grapples with is the changing value of money over time. Even in the absence of inflation, if someone offered you $100 right now versus $100 in a year, the economically rational choice would be to take the $100 today. After all, a lot can happen in a year—and you could invest the $100 in the meantime. But what if the offer were $105 or $110 a year from now?

To convert future benefits into today’s dollars, economists use a “discount rate” that accounts for risk and the preference for receiving payments sooner rather than later. A discount rate is “like the foreign exchange rate between consumption today and consumption tomorrow,” Goldstein said.

The choice of the discount rate can make a big difference in how future costs or benefits are calculated, and it’s often a pivotal factor in studies of the economics of climate change. In the snowpack paper, the authors use three discount rates—1%, 3% and 6%—although they omit the 6% rate in their final valuation “because it is fairly extreme and unlikely to be correct in a water-stressed future world.”

The higher the discount rate, the more heavily future losses are discounted, reducing the economic justification for acting today, such as acquiring new water supplies or building additional reservoirs.

Assumptions about the discount rate, the price of water and future climate trajectories all weigh heavily on estimates of the value of the snowpack’s water. In summary, the authors conclude that about 162 million acre-feet of water is deposited as snow in Western mountains each winter. If half of that snowfall were to fall as rain in the future—and two-thirds of that water were to run off to the ocean without being captured—water systems would lose roughly 53.9 million acre-feet per year. That volume is roughly the combined storage capacity of Lake Mead and Lake Powell, the nation’s two largest reservoirs.

The total replacement cost for the lost water ranged from $120 billion to $4.76 trillion, according to the 2017 study. By comparison, the federal government’s budget totaled about $3.85 trillion in fiscal year 2016.

“To date, a full financial evaluation of the importance of snow in our lives has not been made, but computations here and elsewhere indicate it is on the order of trillions of dollars,” the authors write.

The snowpack’s importance and value vary across the West, with some watersheds more dependent on snowmelt than others. To estimate the local impacts of future snowpack losses, researchers used data from the 2017 study and another paper to create an interactive map that shows the share of water in each Western river basin derived from snow and lets users adjust key variables, including the discount rate, the price of water and the rate at which snow transitions to rain.

Investing in snow science

Jessica Lundquist, a professor of civil and environmental engineering at the University of Washington, called the paper “interesting and unique.” Lundquist, who wasn’t an author of the study but is acknowledged for advising the researchers, said the paper not only tried to put a dollar value on the snowpack but “also was trying to put a value on the knowledge.”

“I like the paper because it was a collaboration between a snow scientist and an economist,” Lundquist said. While the estimates of the snowpack’s value are uncertain, Lundquist said the study provides a useful framework for assessing the financial implications of water management strategies.

In a commentary on the 2017 paper, subtitled “Investments in snow pay high-dollar dividends,” Lundquist wrote that the study “puts the value of snow one thousand times higher than the estimates of snow based on tourism alone.”

When the commentary was published, snow scientists were trying to convince NASA to launch a satellite mission to study the snowpack.

“We were often getting questions about what is the value not only of snow, but of studying snow,” Lundquist said.

A satellite dedicated to monitoring snow never launched. But scientists continue to track the snowpack using other spacecraft, along with a suite of tools that includes aircraft, automated stations and manual measurements.

“I think we’re getting progressively better at figuring out how much snow is in the mountains,” Lundquist said. “I think we’ve made tremendous progress in the last 10 years that we can actually quantify it quite well with a number of ways.”

In other parts of the world, however, snowpack monitoring may be very limited. “A lot of what still needs to be done is in other mountain ranges, other places that don’t have these observing networks,” Lundquist said. “There’s a lot of people who depend on water from the Himalaya who just have no idea whether it’s going to be a drought year or a flood year or what is upstream at all.”

Recreational impact of a shrinking snowpack

Beyond supplying water, the West’s snowpack also underpins the region’s winter recreation economy.

During the 2024–25 season, U.S. ski areas recorded 61.5 million skier visits, according to the National Ski Areas Association. This winter, however, visitation across much of the West has suffered amid a widespread snow drought.

In January, Vail Resorts, which is publicly traded on the New York Stock Exchange, reported that visits to its mountains so far this season were down 20% compared to last season, primarily because of poor snow conditions. In the Rockies, only about 11% of the company’s terrain opened in December, when snowfall was nearly 60% below the 30-year average.

A number of studies have examined how changes in the snowpack affect ski areas—both historically and in future projections.

Between 1999 and 2010, the U.S. downhill ski industry lost an estimated $1.07 billion in revenue between low- and high-snowfall years, resulting in 13,000 to 27,000 fewer jobs, according to a 2012 analysis by University of New Hampshire researchers. The report was commissioned by Protect Our Winters and the Natural Resources Defense Council, two advocacy groups.

A 2024 study estimated that U.S. ski areas lost more than $5 billion from 2000 to 2019 due to fewer visits and higher snowmaking costs. Compared to the 1960-1979 period, ski seasons from 2000 to 2019 shortened by 5.5 to 7.1 days, according to a model of operations at 226 ski areas.

Looking ahead, the study projected that by the 2050s, ski seasons would shrink by 14 to 33 days under a low greenhouse gas emissions scenario and by 27 to 62 days under a high-emissions pathway. Under those scenarios, annual industry losses ranged from $657 million to $1.35 billion.

The 2024 study accounted for the added expenses of snowmaking, which requires investments in equipment and labor while also increasing water and energy use. It did not, however, include the broader ripple effects of shorter ski seasons on surrounding communities, where hotels, restaurants, bars, retailers, and gas stations depend heavily on tourists’ spending.

A 2017 study examining future climate impacts on skiing and snowmobiling analyzed 247 winter recreation locations across the continental United States and projected how warming would shorten seasons. The authors concluded that “virtually all locations are projected to see reductions in winter recreation season lengths, exceeding 50% by 2050 and 80% in 2090 for some downhill skiing locations.”

Those shorter seasons “could result in millions to tens of millions of foregone recreational visits annually by 2050, with an annual monetized impact of hundreds of millions of dollars,” the researchers wrote. They also noted that limiting greenhouse gas pollution “could both delay and substantially reduce adverse impacts to the winter recreation industry.”

A smaller, less reliable snowpack can also affect summertime recreation by reducing streamflows and reservoir levels that support fishing, boating and other water-based activities.

In Colorado, for example, outdoor recreation accounted for 3.2% of the state’s gross domestic product in 2023, according to the Bureau of Economic Analysis. Boating and fishing generated $689 million in economic activity in the state, while snow-related recreation was valued at $1.56 billion—more than any other state.

Other benefits—and costs—of snow

The snowpack’s importance to winter recreation and the West’s water supply are among the easier values to quantify, but they’re not the only benefits snow provides.

On a global scale, one of the most valuable functions of frozen water is that it reflects far more sunlight than bare ground or open ocean. This reflectivity—a property known to scientists as albedo—helps cool the planet.

A 2013 study examining the thawing Arctic attempted to monetize the loss of that cooling effect. The decline in Arctic snow and ice—along with increased methane emissions from melting permafrost—was estimated to cost society $7.5 trillion to $91.3 trillion from 2010 to 2100. “The frozen Arctic provides immense services to all nations by cooling the earth’s temperature—the cryosphere is an air conditioner for the planet,” the scientists wrote.

Then again, the loss of snow could reduce some costs to society.

“There’s some side benefits,” Goldstein said. “You might not have a flood because you’re not going to have a massive runoff all at the same time. That does happen. Some things will be reduced.”

If snow disappeared, so too would snow days that disrupt travel and hamper economic productivity. Winter road maintenance accounts for roughly 20% of state transportation department maintenance budgets, according to the Federal Highway Administration, which estimates that state and local agencies spend more than $2.3 billion annually on snow and ice control annually.

Between 1980 and 2024, the United States experienced 24 winter storms that each caused more than $1 billion in damages, according to the National Centers for Environmental Information. Collectively, those disasters cost $104.2 billion and claimed 1,453 lives.

While vehicle crashes, skier visits and acre-feet of snowmelt can be quantified and priced, snow’s benefits and costs also encompass many things that are difficult—if not impossible—to calculate.

In many ecosystems, for example, snow and snowmelt are vital for plants and animals that have their own economic value, not to mention their intrinsic worth. The 2017 snowpack study did not attempt to price these so-called ecosystem services, which include keeping forests healthy, maintaining cold-water fisheries and sustaining biological diversity.

Even more challenging to value are the mix of emotions that snow evokes. Beauty—and misery—are in the eye of the beholder.

“Some people want their white Christmas,” Lundquist said, “and others are like, please don’t shut down my city.”

This story was produced by The Water Desk, an independent journalism program at the University of Colorado Boulder’s Center for Environmental Journalism.

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Snow and ice underlie the sports of the Winter Olympics, so with the competition about to begin in Italy, there has been a flurry of recent stories about how climate change is affecting the Milan Cortina Games and the event’s future.

With enough refrigeration—and associated greenhouse gas emissions—indoor sports such as hockey and skating could theoretically take place anywhere in the world, during any season. NHL games, for example, are already played in warm climates, including South Florida, Tampa Bay, Las Vegas, Los Angeles, and, until recently, the Phoenix area.

But for outdoor events, such as skiing and snowboarding, weather and climate remain pivotal—and increasingly problematic.

For decades, the Olympics have featured not only fierce struggles among athletes but also an increasingly pitched battle between organizers and Mother Nature—one that has required escalating measures to ensure there’s enough frozen water to support the Games.

“The tenability and success of future Winter Games will depend on whether the international community achieves the temperature goals of the Paris Climate Agreement or remains on track for global warming near 3°C,” according to a January 20 study in Current Issues in Tourism, which I summarize below along with other peer-reviewed research on the Winter Olympics.

The Games were first held in Cortina d’Ampezzo in 1956, but that location in the Italian Alps now experiences 41 fewer freezing days per year (a 19% decline), according to Climate Central, a nonprofit that describes itself as “policy-neutral.” As shown in the chart below, average February temperatures in Cortina have warmed 6.4°F over the past 70 years.

Snowfall in the Alps has been decreasing, as The New York Times reports:

Across the entire southern Alpine region, the average depth of winter snowfall has declined by more than 25 percent since 1980, according to a 2024 study of a century of snowfall records published in the International Journal of Climatology.

Once again, this year’s competition will make heavy use of artificial snow. In the 2022 Beijing Games, 100% of the snow was machine-made, according to a 2022 story in Time. The figure was about 80% in the 2014 Sochi Games in Russia and as high as 98% for the 2018 Pyeongchang Games in South Korea.

Although some athletes have complained about the manufactured snow, others actually prefer the icy, consistent surface in their sports (more on this below). For details on snowmaking at this year’s games, see this Associated Press story about the Italian expert who is responsible for supplying several courses with what he calls “technical snow.” Two reservoirs—each holding tens of millions of gallons of water—were built to support snowmaking at the Milan Cortina Games.

A quick guide to research on the Winter Olympics and climate change

In addition to journalism, there’s a growing body of peer-reviewed research examining how climate change could affect the Olympic Winter Games and the athletes who compete in them.

Below are brief, plain-language summaries of five studies published since 2014 in Current Issues in Tourism. All were co-authored by Daniel Scott, a professor of geography and environmental management at the University of Waterloo in Canada and one of the leading researchers studying climate change impacts on the Winter Olympics.

“When we say climate-reliable, that means, ‘Can you deliver the high-quality snow for competition 90% of the time,’” Scott said in a story by Bob Henson at Yale Climate Connections. “We’re never saying that’s foolproof … We’re using the best available scenarios, but that’s not to say climate change couldn’t throw yet another curve ball at future hosts.”

• The future of the Olympic Winter Games in an era of climate change. Scott et al. (2014).

This seminal paper projected how climate change could affect the ability of past Winter Olympic host cities to provide naturally cold, snowy conditions suitable for outdoor events. The researchers used two key indicators: the probability of a minimum temperature below 0°C (32°F) and snow depths exceeding 30 centimeters (11.8 inches).

During the 1980-2010 period, all 19 former hosts had suitable climates. By the 2050s, however, the number of reliable locations among former hosts fell to 11 in a low-emissions scenario and 10 in a high-emissions pathway. In the 2080s, only six former hosts would remain “climatically suitable” in the high-emissions scenario.

• Weather risk management at the Olympic Winter Games. Rutty et al. (2014).

Researchers examined how weather affected the Games from 1924 to 2010—and how organizers have responded to the changing conditions. “Analysis reveals that while weather-induced impacts have always been a part of the Games, these impacts would be far greater if not for technical climatic adaptations,” the authors write.

The average daytime temperature at Winter Olympic host sites increased from 0.4°C (32.7°F) at the Games held between the 1920s and 1950s to 7.8°C (46.0°F) at the 21st-century competitions. The timeline below shows how the Winter Olympics has increasingly relied on adaptations—from snow compaction and indoor venues to snowmaking and refrigerated tracks—to manage weather risks as temperatures have risen.

• Climate change and the future of the Olympic Winter Games: athlete and coach perspectives. Scott et al. (2022).

It’s one thing to watch the Olympics, but what do the athletes themselves think of how conditions are changing as the planet warms? This study surveyed 339 elite athletes and coaches from 20 countries to define “fair and safe conditions for snow sports competitions.”

The researchers concluded that the likelihood of unfair and unsafe conditions has risen over the past half-century across 21 Winter Olympic venues. “The probability of unfair-unsafe conditions increases under all future climate change scenarios,” the researchers write. “Athletes expressed trepidation over the future of their sport and the need for the sporting world to be a powerful force to inspire and accelerate climate action.”

The chart below shows how the respondents rated both weather conditions and organizers’ responses on a spectrum from ideal to unacceptable across three dimensions: safety, fairness, and performance. At first glance, some of the results may seem paradoxical. “Fresh powder” is rated as one of the most unacceptable features, while “hardpack snow” and “ice” rank among the most ideal conditions—precisely the opposite of what most recreational skiers and snowboarders prefer. But in elite competitions, speed, consistency, and predictability—not fun, soft, and forgiving snow—are what athletes tend to prioritize. Ice illustrates the tradeoffs: despite a moderate safety rating, it ranks highly for fairness and performance.

• Climate change and the climate reliability of hosts in the second century of the Winter Olympic Games. Steiger and Scott (2024).

This study analyzed the climate reliability of 93 potential host locations for snow sports at the Olympic and Paralympic Winter Games. Under a mid-range scenario for greenhouse gas emissions, the authors concluded that only 52 locations would be reliable choices for the Olympics in the 2050s, falling to 46 in the 2080s.

The outlook is even more constrained for the Paralympic Winter Games, which take place later in the season. Under the same emissions pathway, the number of climate-reliable Paralympic host locations drops to 22 in the 2050s and 16 in the 2080s.

The study notes that “a low emission future poses a much lower risk to the number of potential host locations that can be considered climatically reliable.” On a positive note, among the locations projected to remain viable under the mid-range climate scenario, all major global regions that have previously hosted the Olympics—North America, Europe (Alps, Scandinavia, Eastern Europe), and Asia—retain multiple potential hosts in the decades ahead.

• Advancing climate change resilience of the Winter Olympic-Paralympic Games. Scott et al. (2026).

Published on January 20, this new paper identifies “a range of strategies to advance the climate resilience of the Winter Olympics-Paralympics.” The options vary from host-city selection and scheduling changes to operational measures, such as stockpiling snow from the previous winter and relocating competitions to higher elevations.

The study examines the challenges posed by the current “one bid, one city” policy, which requires a host to stage both the Olympics (February) and the Paralympics (March). Because the climate generally is more problematic in March, “this has the effect of significantly reducing the number of climate reliable potential hosts.” Holding both games simultaneously in February is “a contentious solution with strong arguments for and against it,” the authors write, adding:

A merger supports full equality of athletes, potentially increasing visibility and sponsorship opportunities for Paralympic sports. There are also potential logistical and financial efficiencies that could attract more hosts. Critics of a unified games voice concerns that Paralympic events might be overshadowed by Olympic events.

A unified event would be more complex, but the competition could be extended from the current 16 days to 20 or 24 to solve scheduling challenges, the paper notes. Other options include holding the Paralympics in February at a different location, or maintaining the “one bid, one city” approach while shifting the events earlier by two to three weeks, but those strategies have their own tradeoffs.

The 2026 paper also tackles the sustainability of snowmaking, which has been used at every Winter Olympics since the 1980 Games in Lake Placid. While the authors note that “reliance on snowmaking will increase in the decades ahead,” the practice has drawn criticism for its environmental footprint.

“There has been a surprising lack of research evaluating the water, energy, and related greenhouse gas (GHG) emissions used in snowmaking, but state-of-the-art snowmaking and grooming systems have been shown to reduce water (20–40%) and energy (up to 70%) requirements significantly over first and second generation systems,” according to the paper.

Learn more: climate change and the Winter Olympics

Here’s a short reading list of journalism stories I found helpful in understanding the topic:

• ‘We’re Rolling the Dice.’ What Climate Change Means for the Winter Olympics. Sean Gregory, Time, January 27, 2026.

• As the Winter Olympics Stares Down a Warming Future, Organizers Must Adapt, Scientists Say. Kiley Price, Inside Climate News, January 27, 2026.

• Italian expert’s manufactured snow will play big role at the Milan Cortina Games. Jennifer McDermott and Pat Graham, Associated Press, January 23, 2026.

• As Winter Warms, Olympic Athletes, Organizers Hunt for Elusive Snow. Eric Niiler, The New York Times, January 21, 2026.

• To survive warming winters, the Olympics will need to change. Bob Henson, Yale Climate Connections, January 21, 2026.

• What Artificial Snow at the 2022 Olympics Means for the Future of Winter Games. Chad de Guzman, Time, February 8, 2022.

Snowpack update: still dismal across most of the West

As I noted in my previous post, much of the West is experiencing a major snow drought, with some locations recording their lowest snowpack in many decades.

I’m sorry to say that not much has improved, and the clock is ticking on this season—for example, the median peak for Colorado’s statewide snowpack is April 8.

In the February 2 map below, all of those red dots indicate monitoring stations where the snow water equivalent is below the 15th percentile. Ugh!

Another way to gauge the snowpack is to map how much land it’s covering using satellite imagery. The chart below from NASA shows that Western U.S. snow cover was tracking at record-low levels for January, based on satellite observations dating back to 2001. More recent data from the National Snow and Ice Data Center show the record lows have continued into February. Oy!

After a slow start this season, California’s overall snowpack was looking OK in early January. The graphic below, however, shows that statewide snowpack (black line) was at just 57% of normal on February 2. “Despite the lack of snow, California has ample water this year, with good rainfall and major reservoirs at 124% of their average levels after three years that brought average or above-average snow,” writes Ian James at The Los Angeles Times.

Precious powder day at Purg

This season, I’ve shot and shared lots of photos of abysmal snow conditions at ski areas. So, in the interest of being a fair and balanced journalist, I feel obligated to show the other side of the story: we finally had a legit powder day on January 24 at Purgatory.

The resort reported 12 inches from the storm, though my own probing with a ski pole didn’t find quite that much. Checking a resort’s snow report can sometimes feel like asking a barber if you need a haircut. Even so, this was easily my best day of the season. It felt both great and strange to make soft turns again—rather than scraping my skis across bulletproof ice, with rocks and plants still peeking through.

Although no new snow has fallen at Purgatory since the last storm, next week’s forecast at least offers a glimmer of hope, with some substantial snowfall possible across the West. Catching up to average feels increasingly unrealistic in Colorado and many other Western states—but in a season like this, we’ll take whatever comes.

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A serious snow drought is gripping much of the American West as record-breaking warmth has dominated the winter so far.

The stark lack of snow is raising the risk of a dangerous wildfire season later this year in a region where many forests are already choked with excess fuel.

And the anemic snowpack is increasing pressure on the troubled Colorado River, where negotiators remain deadlocked over how to share cutbacks amid declining flows and relentless demands.

The January 21 map below shows snow water equivalent—a measure of the snowpack’s water content—in river basins across the region. Basins in red are below 50% of the 1991-2020 median; orange indicates 50% to 69% of normal.

In a January 8 update, the National Integrated Drought Information System reported that the West’s January 4 snow cover was the lowest for that date in the satellite record since 2001. “Every major river basin in the West experienced near-record or record warmth through December 2025, inhibiting the accumulation of snow,” according to the update.

The graphic below shows statewide temperature rankings for December 2025. Nine Western states had their warmest December on record (dating back to 1895), and Idaho had its second-warmest.

Drilling down to the county level, the two images below show temperature and precipitation from October through December. The top panel illustrates that many Western counties experienced their warmest three-month period since 1895 (red shading). The bottom map compares precipitation to the 1901–2000 average—and reveals that many of those same areas were actually wetter than normal during the last three months of 2025.

In parts of the Pacific Northwest, for example, this winter has brought a “warm snow drought,” where higher temperatures—not a lack of moisture—have prevented snow from piling up. In other places, precipitation has also been below normal, creating a “dry snow drought.”

The West’s lean snowpack has also hurt ski areas, which have struggled to open terrain—and make snow during warm spells. I skied Crested Butte over the MLK Day weekend, and the lack of lift lines during a normally busy holiday was striking.

Last week, Vail Resorts reported that visits to its resorts were down sharply, primarily due to the lack of snow. In the Rockies, only about 11% of the company’s terrain was open in December because snowfall was nearly 60% below the 30-year average, according to The Wall Street Journal.

Here in southwest Colorado, a local ice-fishing tournament at Vallecito Reservoir was cancelled because the lake was ice-free.

At this point, many parts of the West could use a Fabulous February, a Miracle March, and/or an Amazing April to build the snowpack to respectable levels. Forecasting months ahead is very challenging, but the January 15 maps below from the Climate Prediction Center tilt toward warmer, drier conditions across the southern tier of the West from February through April. The Northern Rockies, meanwhile, are projected to be cooler and wetter than normal.

Although we’re currently in a La Niña pattern, federal forecasters say there’s a 75% chance of a transition to “neutral” conditions from January through March, with increasing odds of an El Niño developing later this year. We’ll see how those shifts in the tropical Pacific shape the West’s weather, but with the end of January approaching, the clock is ticking on this winter’s snowpack.

In a recent story in The Washington Post, Ben Noll and Ruby Mellen point to another possible driver of the unusual winter drought, which is also affecting parts of the South and East:

. . . a persistent marine heat wave in the North Pacific Ocean has caused the northern branch of the jet stream to blow strong and farther north, more frequently toward Alaska and occasionally toward the Pacific Northwest and California, where December brought destructive flooding events.

Marine heat waves are becoming more common and intense amid a warming climate.

For more on how this snow drought is unfolding, here are a few recent stories:

• Series of big storms are needed to make up huge snow supply gap, Colorado water experts say. Shannon Mullane, The Colorado Sun, 1/21/26.

• The western US is in a snow drought, raising fears for summer water supplies. Andrew Freedman, CNN, 1/9/26.

• Utah’s snowpack is at a record low. Here’s what the latest water forecast shows. Brooke Larsen, The Salt Lake Tribune, 1/9/26.

• Where’s the snow? For these places, there hasn’t been much this season. Ben Noll, The Washington Post, 1/8/26.

• The western US is in a snow drought, and storms have been making it worse. Alejandro N. Flores, The Conversation, 1/8/26.

SnowSlang: O is for “orographic lift”

SnowSlang is my occasional look at the language of snow. More at snowslang.com.

Orographic lift occurs when air is forced up over a mountain range or other elevated terrain. As the air mass rises, it expands and cools (roughly 5.5°F per 1,000 feet of elevation gain in dry conditions). Water vapor condenses into clouds, which can produce precipitation—essentially “wringing out” moisture as the air climbs.

This is why the windward sides of mountains are often wetter than the leeward slopes, where a drier “rain shadow” can form. The American West has many classic examples of the orographic effect, including the Sierra Nevada and Cascades: storms roll in from the Pacific, dump moisture on the west side, and leave areas east of the mountains parched.

Even hundreds of miles inland, wind direction plays a major role in where storms deliver the most moisture. Some ski areas do better with a southwest flow, while others are favored when storms come in from the west or northwest.

OpenSnow puts it this way:

When forecasting snow for mountains in your area, the biggest forecasting secret is to find the wind direction that favors rising air. Wind flowing freely, hitting a mountain head-on, and being forced to rise will create the heaviest snowfall.

You may also hear the term upslope snow to describe this process. Along Colorado’s Front Range, upslope storms push moisture from the Great Plains toward the mountains, where the Rockies force that air upward and can produce impressive snowfall.

Upslope storms have even inspired a Boulder-based brewery that lists “snowmelt” as one of its ingredients. Upslope Brewing Company describes an upslope storm as “a front range-covering, water-table-filling, snow-dumping weather pattern that anyone with bindings and a roof rack would die for.”

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I reported this story for The Water Desk, an independent journalism initiative at the University of Colorado Boulder that I co-direct. It’s a deep dive into how we measure the West’s snowpack—an increasingly high-stakes question as climate change reshapes water management.

A controversial recent study highlights an old truth about the American West’s snowpack: it’s difficult to measure—and just as hard to forecast how much of its water will ultimately reach tens of millions of people and vast swaths of farmland.

Water managers have increasingly turned to aircraft that use lasers to gauge the snowpack across entire basins. But the Aug. 15 scientific paper argues for a less expensive strategy: focusing new monitoring efforts on a select number of locations known as “hotspots” that excel at predicting how much water will run off from the snowpack—a frozen reservoir that can change dramatically over short distances.

Snowfall rates vary widely with elevation, and the amount of water locked in falling snowflakes shifts from storm to storm.

On the ground, snow accumulation depends on the wind, the forest canopy overhead, the exposure to the sun and the amount of dust that lands on the snowpack. Even a homeowner armed with a ruler can find very different snow depths depending on where they poke in their backyard.

For water providers, knowing how much water is stored in the snowpack is essential. In much of the West, snowmelt supplies most of the runoff that flows through streams, rivers, reservoirs, irrigation canals and household faucets.

If water managers overestimate the snowpack, their customers can be left high and dry later in the year. But if analysts underestimate streamflows, reservoirs can fill faster than expected—raising the risk of disastrous flooding.

With climate change making the snowpack less reliable and redefining what “normal” means, the pressure on forecasters is intensifying in a rapidly growing region with a well-documented gap between water supply and demand. Even a perfect knowledge of the snowpack’s water content doesn’t guarantee accurate streamflow projections because factors such as soil moisture, groundwater levels and late-season weather cloud the picture.

Scientists and water managers, aware of the high stakes, began formally measuring the snowpack to make water forecasts more than a century ago. They selected key locations in the high country, plunged hollow metal tubes into the snow and weighed the extracted cores to calculate the water content—a technique still used extensively today.

During the late 20th century, officials installed hundreds of automated stations across the West’s watersheds as part of the SNOTEL network. These sites use “snow pillows” to measure the weight of the overlying snow and estimate its water content. Forecasters then correlate these long-term snow records with historical streamflows to predict a basin’s water supply.

In the 21st century, airborne snow surveys have expanded rapidly. Aircraft equipped with lidar—a laser-based technology—precisely map the snow depth across entire watersheds while an onboard spectrometer scans the snowpack’s reflectivity. Snow depth is determined by subtracting lidar readings taken when snow is absent from those taken when snow is present. Scientists combine those measurements with estimates and observations of snow density to calculate the water content, known as the snow water equivalent.

Satellites also provide valuable data on the snowpack, especially its extent on the ground, but reliably measuring snow water equivalent from space remains elusive. Clouds and forests can also obscure or complicate a satellite’s view.

While technologies that estimate an entire watershed’s snowpack are on the rise, the recent hotspots study argues that water forecasters could gain crucial insights by targeting future monitoring at a limited set of locations.

The authors say these 62-acre hotspots not only are strong predictors of how much water will run off in the spring and summer, but also could be more cost-effective than mapping the snowpack across a whole watershed using aircraft. That approach has become more common due to the work of Airborne Snow Observatories, Inc. (ASO), a company that spun out of research at NASA’s Jet Propulsion Laboratory.

“The greatest gains in water supply prediction come from leveraging existing stations and expanding snow measurements to the right places, rather than everywhere,” the authors write in Communications Earth & Environment.

But in the tight-knit world of Western snow science, the paper has sparked pushback from supporters of airborne snow monitoring.

Jeff Deems, a co-founder of ASO, said the paper is a “statistical curiosity” and criticized both its methodology and the conclusions it draws about snowpack monitoring.

“Our datasets have become the gold standard, the benchmark against which others are evaluated,” Deems said.

The Colorado Airborne Snow Measurement (CASM) program produced a strongly worded critique of the study, which used a proxy for the ASO data, rather than actual measurements from aircraft.

“Although this paper is published in a well-known journal, it makes unsupported, misleading and editorialized claims about the cost, value, and performance of airborne lidar for streamflow forecasting,” said the rebuttal from CASM, a group of stakeholders whose planning team includes ASO, water providers, the Colorado Water Conservation Board (CWCB) and other organizations. “The authors make a series of critical logic and analysis errors which when combined with their over-broad conclusions result in a very misleading paper.”

But study co-author Cam Wobus wrote in an email that the paper “might have struck a nerve” because “it showed that wall to wall measurement of snow may not be needed to create more accurate water supply forecasts, which ASO could have perceived as a threat to their business model.”

Despite the sharp differences among snow researchers, experts agree there’s no silver bullet for monitoring the snowpack or predicting streamflows. As warming temperatures and evolving storm patterns continue to transform the snowpack, both old-school methods and newer technologies will be needed to better manage the region’s scarce water resources.

“Snowpack estimation and streamflow forecasting is a vast and unsolved field of research,” the CWCB wrote in response to questions from The Water Desk.

Although CWCB’s logo was included at the bottom of CASM’s rebuttal, the agency said in an email that the document “should not be misconstrued as an official position statement” and that “CWCB has acted as a funding and coordination partner” to CASM.

Searching for snowpack hotspots

The hotspots study set out to test an intuitive idea: in high-elevation watersheds, the snowpack in certain locations can be especially useful for predicting streamflow.

“There are places within drainage basins that, if you train your water-supply forecast on the snow record in those locations, you’ll have a better forecast than if you use the basin average,” said co-author Eric Small, a professor of geological sciences at the University of Colorado Boulder.

“If you think about a drainage basin, there’s going to be places in that drainage basin where there’s not a lot of snow, or there’s not much connection between the snowmelt and the runoff,” Small said. “There’s going to be other places in the basin where there is a lot of snow and a lot of connectivity between the snowmelt and the runoff. So it should not be a surprise that there’s locations within a basin that are more predictive of this seasonal water supply.”

In general, locations with the deepest, most persistent snow are more likely to be hotspots.

“Anyone who’s seen a basin in Colorado and sees the south-facing slopes that are bare of snow and the north-facing slopes that have snow three feet deep in the springtime recognizes that once you take an average across all of that, the stuff on the south-facing slopes isn’t going to matter at all,” said Wobus, a principal at CK Blueshift, LLC, a consulting firm that works on water and climate issues.

“It’s silly to fly an entire basin if 30% of that basin doesn’t have any snow on it, so that’s an easy fix right there,” Wobus said.

While hotspots typically accumulate lots of snow, what’s happening beneath the snowpack is just as important. “The hotspots are locations where there’s both a lot of water, and when it melts, a large fraction of that water would get into the stream,” Small said.

Hotspots tend to have shallow or relatively stable groundwater storage and soil moisture levels that don’t vary year to year.

“The hotspots are places where there’s either enough snow or minimal enough variations in storage that the water is getting to the stream and the water is getting to the stream at the right timescale,” Small said.

Each basin may have numerous hotspots. “The hotspots weren’t unicorns,” Small said. “There were many possible hotspots. We had an objective measure to choose the official hotspot in the paper, but you could have chosen many other locations that were also predictive.”

Once a hotspot is identified, the authors outline several potential ways to tap its predictive power. One option is to add a new SNOTEL station at the site, although that may not be feasible because of the terrain or land protections. Another possibility is to use remote sensing from a plane or a drone. The authors write that one or two flight paths that observe the hotspot could gather data “at a substantially lower cost than more conventional wall-to-wall basin coverage.”

Even recreationists could help gather data from snowpack hotspots. “You could use citizen science to do it. You could send a bunch of backcountry skiers out to your location for fun, give them an app,” Small said. “They’re probably already going there. If you saw where people were skiing, they would probably have mapped out the hotspots already.”

A shortcut, or a statistical trap?

Critics of the hotspots paper agree that some parts of a watershed can carry more predictive weight for streamflows than others.

“It’s not a new concept, and it’s a very seductive one. It’s essentially the premise behind the SNOTEL network,” Deems said.

But to some scientists who dispute the study, hotspots can hide as much as they reveal—and potentially mislead water managers as the West’s climate evolves and as the hydrology of high-country landscapes is reshaped by disturbances, such as the increasing frequency of wildfires.

“Even if they did everything right—found these hotspots—the likelihood of them retaining the same statistical predictive power going forward is essentially nil,” Deems said.

The rebuttals to the paper have challenged both its analysis and the real-world implications the authors infer from their results.

Noah Molotch, a professor of geography at the University of Colorado Boulder and director of the Mountain Hydrology Group at the Institute of Arctic and Alpine Research, said “the study doesn’t accurately portray the direction that water managers have been moving for a couple of decades now.”

“My concern there is that it takes us further down the path of being blind to the spatial patterns that govern water supply and that can lead to surprises for water managers,” Molotch said.

Although the hotspots study has implications for airborne snowpack monitoring, the paper didn’t analyze data gathered by aircraft, which has been collected only in select watersheds and over a shorter time period than the authors examined.

Instead, one of the ways the researchers probed the snowpack in 390 basins in the West was to combine satellite data from 2001 to 2023 with historical weather data. The satellite images, collected by the MODIS instruments aboard two NASA spacecraft, show the fraction of each pixel covered by snow and the reflectivity of the snowpack, among other metrics. Each pixel is a square with 500-meter (1,640-foot) edges.

The authors argue that this type of data serves as a reasonable “proxy” for the basin-wide estimates that could be obtained from prospective satellite missions and current airborne monitoring. Small said five different datasets were examined, and all showed similar results.

But the CASM critique argues that the proxy dataset has “a demonstrated average error of 35% (ranging from 20-60%)” when compared to airborne lidar, and its much coarser resolution further limits its utility.

The paper’s authors “make the assertion that that dataset has been shown to be accurate and, in their language, therefore serves as a reliable proxy for airborne lidar,” Deems said. “That assertion is incorrect, and that undercuts the entire rest of the paper, sadly.”

Deems said the study used the date of snow disappearance to back-calculate how much snow was there while also “blending in an atmospheric model precipitation product, which is highly uncertain.”

By contrast, Deems said, ASO creates “a highly accurate map of snow depth throughout the watershed,” which is then paired with estimates of snow density informed by SNOTEL measurements and hand-dug snow pits. What emerges, he said, is a basin-scale estimate of snow water equivalent that’s within about 1% of the actual volume.

“That’s better than we can measure streamflow,” Deems said.

Video: Colorado’s Northern Water explains how the utility uses ASO data.

Clashes over the merits of datasets are grist for the academic mill, but critics raise a broader concern: the paper takes a retrospective look at snowpack-streamflow relationships in an age of extreme weather and shifting baselines.

Scientists have an awkward name for this pivotal issue: “stationarity.” In simple terms, it’s the assumption that the past is a reliable guide to the future. But just as mutual-fund disclaimers warn that past performance is no guarantee of future returns, climate change is making historical patterns less trustworthy.

Storm tracks are migrating. Warmer temperatures mean more winter rain and less snow. Rising evaporation rates are drying out soils. And both the timing and volume of runoff are in flux as the weather changes and high-elevation wildfires remake watersheds.

One widely cited 2008 paper in the journal Science framed the problem bluntly with its title: “Stationarity Is Dead: Whither Water Management?”

The hotspots strategy, according to the CASM rebuttal, “does not test whether those sites remain predictive under shifting climate conditions or extreme events” and “what looks like a hotspot in the historical record may fail under current or future conditions.”

What to do with hotspots?

On a practical level, the hotspots paper argues that snow researchers and water managers could mine these locations for essential data by installing additional SNOTEL stations or using remote sensing. But critics say several big hurdles stand in the way of implementation, many of which are acknowledged in the study.

First, a hotspot with 500-meter edges covers nearly 2.7 million square feet, but the snowpack may vary greatly within that footprint. Where in that area should a new SNOTEL monitoring station go? Cost is another concern. “Installing and maintaining a station is not cheap either—$100,000 easily between gear and personnel time and maintenance,” Deems said.

Second, terrain and land-use rules can make installation impractical or illegal. “In many cases, it’s going to be impossible to put a station there, either because it’s sloped and the snow pillows don’t work on slopes, or because it’s in the wilderness or in avalanche terrain or something like that,” Deems said. Drone flights—another potential monitoring tool—are also prohibited in federal wilderness and face their own logistical challenges.

Third, any new station only generates data going forward. It doesn’t provide the long historical record that water managers need to train their models and make streamflow predictions. “It’s not going to be useful until you probably get about 30 years of data,” Molotch said, “and then let’s think about how much the climate may have changed over those three decades.”

At its core, the dispute over hotspots reflects a long-standing divide in hydrology. One camp relies on statistically based approaches, such as using a select number of “index” sites to measure the snowpack and predict streamflow based on historical records. Another paradigm favors physically based methods that employ the laws of physics to account for the coming and going of water molecules in a basin, such as using aircraft to map the snowpack.

“Historically, we’ve increasingly been moving toward physically based approaches in hydrology,” Molotch said. “At some point, we may have a complete passing of the baton toward physically based approaches. I don’t know if and when that will be in our future, but I think that that is the way that things are migrating over time.”

Small said that ASO data “will give you the total number of water molecules in a basin” if you accept their snow density model, but that’s only part of the story. To predict streamflow, forecasters must account for other factors, including how much water is lost to the atmosphere when it evaporates, transpires from plants or converts directly from ice to water vapor, a process known as sublimation. Soil moisture and groundwater levels also shape the hydrologic cycle.

“The total volume of water in the snowpack is not hugely predictive of streamflow compared to what you get from the hotspots, and that has to be the case,” Small said. “If you have any variations in the basin from evapotranspiration or soil moisture storage or groundwater storage—that has to be the outcome. And I think we probably should have said that in the first sentence of the paper.”

Using an “all of the above” approach

Denver Water describes the snowpack in the mountains west of the city as the utility’s biggest reservoir. To supply its 1.5 million customers, Denver Water uses a variety of techniques to track the snowpack, including manual measurements, automated SNOTEL stations, ASO flights above key watersheds and satellite data that is blended into reports that Molotch and colleagues generate at the University of Colorado Boulder.

“We take an all of the above approach,” said Taylor Winchell, climate change adaptation program lead at Denver Water. “We think that all of these systems really have their place and are all important in giving us the full picture of the snowpack that we’re hoping to gather to help us make confident decisions.”

Each type of snow monitoring has its benefits and limitations. “They each fill a gap that the other doesn’t,” Winchell said.

The SNOTEL system, for example, can provide hourly or daily readings of the snowpack and offers long historical records, but it only measures conditions at a single point. The stations also tend to sit in mid-elevation clearings that are easy to access, so they don’t necessarily reflect the diversity of the West’s terrain and overlying snowpack.

“We often don’t have measurements at those higher elevations, and it kind of leaves a blind spot in our understanding of the snowpack,” Winchell said.

Like many water providers in the West, Denver Water has been grappling with a growing mismatch between snowpack levels and the amount of water that eventually reaches streams and rivers in the spring and summer.

“We just don’t quite expect the same amount of streamflow production nowadays as we would’ve historically with similar levels of snowpack,” Winchell said, noting the influence of soil moisture levels, evaporation and sublimation. “We can’t go off the same assumptions that we might’ve had in the past, and so every year it creates this kind of new and intensified challenge to understand how the snowpack is going to translate into streamflow.”

Denver Water has used ASO data since 2019 and spent an average of about $200,000 per year on the airborne surveys. That first year, ASO surveyed the watershed around Dillon Reservoir—a linchpin in the utility’s supply that collects runoff west of the Continental Divide so that it can be pumped through a 23-mile tunnel bored beneath the Rocky Mountains and reach the east side of the Divide, where most of Colorado’s population lives.

“With those flights, we saw kind of immediately the high value of this information for our decision-making processes,” Winchell said. ASO found the snowpack was bigger than what Denver Water expected, Winchell said, so the utility “immediately increased outflows from Dillon Reservoir so that we’d be able to capture that snowpack without flooding downstream of the reservoir.”

ASO’s high-resolution data is valuable for Denver Water because it “fills in the gaps between those station measurements,” Winchell said.

In the large watersheds that supply the utility, “you can have storms and snow patterns that are quite different from one side of the watershed to the other, and you might have different diversion systems in each part of that watershed,” Winchell said. “You might have had a forest fire in one part of the watershed that impacts the snowmelt within that sub-watershed. So really being able to have that detailed picture of the full watershed, we do find value in that.”

But the cost of airborne surveys remains a critical issue.

“It’s still been a struggle year over year to get the funding needed even to fly what we see as the baseline number of useful flights,” Winchell said. “There’s still a lot of room for both adding additional flights in watersheds that are already being flown, as well as conducting ASO flights in watersheds throughout the state that don’t currently have ASO flights.”

Costs versus benefits

In Colorado, CASM was formed in part to secure additional funding to expand ASO flights above the state. CASM’s annual budget in 2025 was $4.5 million, with state funding accounting for 52% and the rest from federal, local and other sources.

The U.S. House of Representatives recently passed bipartisan legislation that would reauthorize and update the federal Snow Water Supply Forecasting Program “to incorporate modern technologies, including LiDAR and satellite imagery, to improve the accuracy of snowpack and water-supply predictions,” according to sponsor Jeff Hurd, R-Colo.

Backers of airborne surveys acknowledge that flights aren’t cheap—two flights over a basin can cost a couple of hundred thousand dollars per year—but they say the data can generate far greater benefits. A more precise read on the snowpack can prevent flooding and allow water managers to devote excess supplies to groundwater recharge. Conversely, advance warning of shortages can help avoid disruptions for both agricultural and urban water users.

“The value of these data can be off the charts,” Deems said, with some case studies from California showing a return on investment between 50 and 200 to one.

In the headwaters of Northern California’s Feather River, which supplies the California State Water Project, Deems said ASO’s data improved water management. In 2021, the year before ASO’s flights began, water managers “thought they had a decent snowpack,” Deems said, but they had to dramatically scale back allocations, eventually to zero, “because the water just didn’t show up,” causing significant impacts to farmers and other water users.

“The following year, we started flying in the Feather River,” Deems said. “Our February flight showed that they had half the water they thought they had, so it looked like essentially a repeat of the prior year, except this time they knew about it in February, rather than finding out about it when the water didn’t show up at the stream gauge in July.”

The future of snowpack monitoring

Looking ahead, the stakes are only growing for snowpack monitoring and streamflow forecasting as the climate warms and the West continues to add new water users.

Despite their varying views, snow experts agree that a diversity of approaches will be needed in the foreseeable future. The hotspots study authors see value in the ASO flights, and backers of airborne surveys would like to see more SNOTEL stations.

“We are first in line to advocate for more observations, especially if they can be in environments that are different than the current set of observations covers,” Deems said.

The question, Wobus said, is “how do we use combinations of advanced monitoring technologies like lidar and satellite observations and things like that in a framework that will help you improve water supply forecasts without having to measure everything?”

“There’s a lot of room to improve the economics of snow monitoring,” Wobus said. “If we’re talking about the difference between flying every basin once a year and getting total coverage at a cost of, let’s say $10 million a year for the state of Colorado, versus adding a few more SNOTEL stations in a few places where you really need it—there’s a lot of real estate in between those two things.”

When ASO maps the snowpack in an entire basin, its aircraft flies back and forth in a pattern often likened to mowing a lawn. Small and Wobus said that one way to save money would be to do more limited flights and use machine learning—a type of artificial intelligence—to extrapolate the results.

“If you fly one strip and combine that with a machine-learning model, you can get like 98% of the way there, and you can save a whole boatload of money,” Wobus said. “You could just fly a straight line across the state of Colorado and then turn around and fly back and get almost as much information as you’re getting by flying like a lawnmower back and forth across the basin.”

But some backers of airborne mapping are skeptical.

“That would be bringing a lack of confidence back into the system, and that’s a difficult thing to ask a water manager to accept, especially after we’ve shown what’s possible,” Deems said.

Drones have also become part of snow hydrologists’ toolbox. While the hotspots paper argues that using lidar technology mounted on drones would be less costly than flying large aircraft, that approach “does not reflect the logistical and financial realities of operating such a program in Colorado’s mountain environments,” according to CWCB.

“Drone-based lidar systems require extensive permitting, frequent flights due to limited range and battery life, and highly trained operators to meet accuracy standards comparable to crewed aircraft,” CWCB wrote. “No program currently exists with the resources, planning, or data management structure to deploy drone surveys at the basin scale needed for operational water forecasting.”

For many snow hydrologists, the holy grail would be to launch a dedicated satellite that could look down from space and estimate the water content of the snowpack around the planet using, for example, microwave sensors. But that’s literally a heavy lift.

“There’s lots in the works,” Deems said. “But the global solution is pretty elusive, and folks have been trying to do this for decades.”

The technology exists today to measure snow water equivalent with a satellite, “but not everywhere and not all the time,” Molotch said. One major obstacle is that satellite monitoring may not work when the snowpack is wet, which is especially vexing in the warmer, maritime snowpacks near the West Coast.

“Snowpack conditions in the Sierra Nevada of California can be wet at any time of year between storms when the sun’s out and it starts to warm up,” Molotch said. “As the climate warms, we would expect that snow wetness will be increasingly problematic for microwave remote-sensing techniques. But I think on the positive side, if we’re able to make snow water equivalent measurements in some locations, that helps us provide information for models that can fill in the gaps.”

In July, NASA and India’s space agency launched NISAR, a new radar satellite built to track how Earth’s surface is evolving. While not dedicated to monitoring the snowpack, the mission will measure changes in snow, glaciers, sea ice, ice sheets and permafrost. Operating day or night, NISAR’s signals can penetrate clouds, and the satellite will observe nearly the entire Earth’s surface twice every 12 days.

The NISAR mission “introduces a promising avenue for cost-effective, large-scale snow depth and snow water equivalent” estimates, according to a January study in Frontiers in Remote Sensing. A 2024 paper in Geophysical Research Letters concluded that NISAR offers a “promising path toward global snowpack monitoring.” While errors increase in forests with a denser canopy, the 2024 study said the satellite “may be feasible for snowpack monitoring in sparse to moderate forest cover.”

What research and data would deepen understanding of the snowpack in the future?

“Where to begin?” Winchell said with a laugh.

In addition to having more manual measurements, more SNOTEL stations, more ASO flights and even a citizen-science effort, Winchell said better knowledge of snowpack temperatures would be helpful to Denver Water because that “provides a really strong indication of when the snowpack is ready to melt.” Additional soil moisture data could also improve the utility’s forecasts of how the snowpack translates into streamflows.

“The field of snowpack research is just a crucial field with really lots of exciting work ahead, especially as these new, really high-value, high-accuracy datasets are coming into play,” Winchell said. “I think decades into the future we’ll wonder how people really went about managing the snowpack water supplies without this information.”

This story was produced and distributed by The Water Desk at the University of Colorado Boulder’s Center for Environmental Journalism.

Editor’s note: Two of the co-authors of the hotspots paper and one of the critics of the study are affiliated with the University of Colorado Boulder. The Water Desk is also based at the University of Colorado Boulder but operates as an editorially independent journalism initiative and is solely responsible for its content.

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Colorado’s snowpack was dismal, but that didn’t stop me from going on a ski road trip across the state over winter break.

Over six days, I skied five resorts—Purgatory, Crested Butte, Breckenridge, Loveland, and Monarch—and conditions were lousy at all of them. I went into the trip with very low expectations, and I wasn’t disappointed.

Even so, I did enjoy the change of scenery and the chance to visit mountains I hadn’t skied in a long time. What follows is a photo essay featuring the bad, the ugly, and a bit of the good from the solo trip.

Across much of the West, a subpar snowpack is doing more than spoiling ski seasons—it’s raising the risk of wildfires, water shortages, and ecological stress later this year.

Purgatory

December 24, 2025

On the way out of town, I did some laps at my home mountain and continued this season’s trend of abusing the bottoms of my skis due to thin or nonexistent cover.

We had a wet fall in southwest Colorado and the rest of the state, but it was also very warm, so rain fell instead of snow. The above-normal temperatures continued into December, which was on the dry side, so like many ski resorts, Purgatory has struggled to produce enough machine-made snow to make up for what Mother Nature hasn’t delivered.

At Purgatory’s base, I cringed at all the bare spots, some of which were also peeking through on open runs higher on the mountain. Two kids were riding a sled down the gentle slope, only to come to a screeching halt where the snow disappeared, yet they didn’t seem to mind.

From Purgatory, I headed north on U.S. 550, which crosses over three mountain passes—Coal Bank, Molas, and Red Mountain—that are all roughly two miles above sea level. Even at those lofty elevations, the snow was scarce. During winter, this gorgeous stretch of highway can get icy and snowpacked, making the curvy route a white-knuckle affair. This time, it was smooth sailing on dry pavement flanked by exposed dirt.

Crested Butte

December 25, 2025

On a gloomy Christmas, Santa delivered rain to Crested Butte. Humanity’s burning of one lump of coal after another has helped make this shift to liquid precipitation more likely—though it’s tough to definitively attribute this one season’s weather to climate change (see this story from Colorado Public Radio for more on that).

Driving up to Crested Butte from my motel in Gunnison, the rain spattering on the windshield was disconcerting, especially since Gunnison is known as Colorado’s icebox because frigid air often pools in the valley during winter.

As with the other resorts I visited, Crested Butte had very limited terrain open. But some of those runs were surprisingly fun to ski because of the warm weather. Overnight, the slopes hadn't frozen solid, so the turns were soft and forgiving, almost like spring conditions.

The precipitation held off during my first hour, but then it started to rain with gusto at lower elevations, changing to a wintry mix as I ascended the mountain on the chairlifts.

Hoping to advance science, I opened a phone app that lets volunteers report the type of precipitation they’re observing so researchers can better understand the crucial rain-snow transition in mountainous environments. The app, which I wrote about in the story below, records your location and elevation, so it was interesting to do a transect on the chairlift ride and log how the weather changed with increasing altitude.

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Loveland

December 26, 2025

As one of the highest-elevation resorts in the nation, Loveland tends to open early and close late in the season, so I’ve skied there in every month from October through June.

Although Loveland’s base is at nearly 11,000 feet and its terrain tops out just above 13,000 feet, there were still big brown patches along the Continental Divide when I visited. On the chairlift, I commiserated about the lack of snow with an old timer who told me he’d been wearing shorts and a t-shirt in Denver the day before.

Before heading back to my motel in Dillon, I drove up nearby Loveland Pass to check the conditions and was stunned by the lack of snow cover above 12,000 feet in late December.

Breckenridge

December 27, 2025

The Saturday between Christmas and New Year’s Day is often one of the busiest times at Colorado ski resorts, but it was eerily quiet at Breckenridge on the day I visited.

Weeks before, when I was planning my trip, I was bracing for big lines at Breck, thinking the place would be mobbed during winter break with out-of-state tourists and Colorado natives from the Front Range. But the queues for the chairlifts were small. And the lodges that would normally be packed with people paying outrageous prices for mediocre food had plenty of available tables.

The place wasn’t completely empty. Many people who had already purchased plane tickets and non-refundable hotel rooms went through with their travel plans. One guy next to me on a chairlift had come out from San Francisco. I apologized for the dreadful conditions, telling him this was the worst start to a ski season I’ve seen since moving to Colorado more than 17 years ago.

Monarch

December 28, 2025

Monarch offered my first powder day of the season—sort of.

Overnight, the mountain received 1” of new snow, but it was super windy, so some of it had blown off by the time I arrived the next morning. It was 11 degrees when I pulled into the parking lot, and the windchill was below zero, but it actually felt good to feel cold during ski season after such a warm start.

Monarch had more terrain open than other resorts, including some steeper black-diamond runs, but the low-tide conditions meant there were lots of ski-wrecking rocks lurking beneath the snow, known as “sharks.”

The night before, in the parking lot of my Salida motel, I dripped molten plastic from a flaming p-tex candle into the many gouges in my bases. The patches didn’t hold at Monarch, and I picked up some more core shots along the way, making me wonder how much longer my 2017 Rossignol Soul 7s would last.

Crested Butte

December 29, 2025

On the way home to Durango, I made an encore visit to Crested Butte, which looked much better clad in white. It even dipped to minus-5 degrees on my drive up from Gunnison.

The storm that brought 1” to Monarch had dropped 7” on Crested Butte. Unfortunately, that fresh snow attracted crowds, so by mid-morning I was waiting in 15-minute lift lines to access the still-limited terrain (people fleeing Telluride—which was closed due to a ski patroller strike—may have also increased visitation).

At Crested Butte, the fresh powder had been skied off the day before, and the slopes were now rock hard from the freezing temperatures.

Upon returning to Durango, the guy at the ski shop gently advised me it was time to convert my aging Soul 7s into “rock skis”—shitkickers meant for marginal conditions, which may be the new normal. After nearly 250 days of service, I’d certainly gotten my money’s worth.

Fortunately, I was able to snag a pair of the Soul 7’s successors online for less than half price, thanks to my ski instructor discount. But given the lack of snow this season, I’ll continue beating up my old skis for the foreseeable future. Even with new snowfall since my trip, Colorado’s snowpack remains far below normal.

Rage against the stoke machine

The skiing was disappointing, but for an environmental journalist on the doom-and-gloom beat, it was a fruitful reporting trip. Sharing bad news is my specialty.

Most of today’s snow and ski journalism is low-value, high-volume fluff that typically accentuates the positive while sidestepping the climate context. The content tends to fall into two camps: fawning advertorial—press releases lightly rewritten to flatter resorts and gear companies—or clickbait engineered to game search engines and social media algorithms through listicles, storm hype, and a steady drip of alpine tragedies that can read like ghoulish tabloid coverage.

My goal here is different. I’m pursuing independent snow journalism that aims to illuminate what’s happening to our snowpack, explore how scientists are studying it, and explain why it all matters for society—even when the news is grim and doesn’t enhance advertising revenue or readers’ stoke.

I want to educate and enlighten, not promote and pretend. I want to analyze data, not traffic in vibes.

That can be a lonely, unprofitable pursuit in a media landscape built around short attention spans and lifestyle enthusiasm. But I believe it’s more important than ever to honestly bear witness to a changing cryosphere—and to document what’s actually happening on the ground.

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Here’s a quick rundown of 10 snow-related stories I’ve been following, including an update on the West’s meager snowpack at the end.

🤖 1) AI informs snowfall forecasts

The liquid content of snow varies from storm to storm and place to place. That’s a major reason why predicting snowfall totals is so challenging—especially in complex, mountainous environments. Sometimes the snow is light and fluffy; other times it’s dense and laden with moisture.

A new study in Weather and Forecasting concludes that machine learning, a form of artificial intelligence, can provide crucial insights into the snow-to-liquid ratio, a key variable for predicting snow accumulation and its water content.

“If you don’t have a good snow-to-liquid ratio, your snowfall forecasts are not going to be as good,” said lead author Peter Veals, a University of Utah research assistant professor of atmospheric sciences, in a university press release.

The researchers used high-quality, manually collected snow data from 14 mountain sites in the West, along with local atmospheric conditions, to train machine learning models. Those algorithms did a far better job at predicting snow-to-liquid ratios than existing methods.

“In simple terms, the new approach will enhance the reliability of snowfall forecasts, which would be helpful for the West’s water resource managers, highway officials, weather forecasters and avalanche professionals who depend on knowing how much water the snow holds,” according to the press release.

🚫 2) Is it OK to eat snow?

Everyone knows not to eat snow that’s yellow or dirty. But Colorado State University snow hydrologist Steven Fassnacht says there can be plenty of other unappetizing things lurking in snow that you should avoid putting in your mouth.

In an interesting interview with CSU’s The Audit podcast, Fassnacht notes that snow can contain dust, forever chemicals, heavy metals, microplastics, and other contaminants. “The big ones that we see around here are nitrogen and sulfur-based,” he said. “They come out of the tailpipe, out of the smokestack, et cetera. So, if you’re downwind from a major industrial source of these, then the likelihood that you have these in the snowpack is a lot higher.”

Because a snowflake has more surface area than a raindrop, it can pick up more chemicals in the atmosphere. And around the planet, scientists are finding that tiny pieces of plastic are everywhere.

“Think about going out in the snow. You’ve got plastic ski boots on and plastic skis and poles, and your jacket and all your equipment, that’s all plastic,” Fassnacht said. “Any breakdown of that—which will happen over time—is going to put microplastics onto the snowpack.”

Other sources note that snow can contain microbes and pesticides. The Cleveland Clinic says, “If the flakes are undisturbed, pristine white and come from the top layer, it’s typically safe to indulge in a scoop.”

Fassnacht, who said he sometimes eats snow himself, offered this advice: “Most of the time you’re probably OK, but you want to really be aware of where you are eating this snow.”

⛷️ 3) Sensitivity of ski resorts to climate change

An analysis of 41 ski areas in Washington, Idaho, Oregon, and California finds that “while many resorts indeed face substantial declines in ski-season snow depth, many of those in Idaho and a few at high elevation are likely to be minimally affected.”

The preprint, which is under review at The Cryosphere, identifies several mitigating factors that could offset warming in some locations, including increased winter precipitation, colder conditions at high altitudes, and historically heavy snowfall. Winter snow also tends to be less sensitive to warming than spring snow, and many resorts span wide elevation ranges that provide a natural buffer.

“Although a warming climate clearly poses an existential risk to winter sports, our analysis shows that this broad-brush picture misses some important exceptions,” the researchers write. “In the western US, the wide variety of climates under which ski resorts operate means that they have very different exposures to climate change.”

🏂 4) How snowmaking works

As ski areas grapple with climate change, they’re increasingly turning to snowmaking to make up for what Mother Nature fails to supply.

Two new stories examine the art and science of making artificial snow—and how much water and energy are needed in the process:

• “Climate change makes snowmaking a necessity, not a backup, for the West’s ski resorts,” Caroline Llanes, Rocky Mountain Community Radio, December 11, 2025 (this story was produced in partnership with The Water Desk, an independent journalism initiative at the University of Colorado Boulder, which I co-direct).

• “How Southern California resorts bring snow to the slopes during warm winters,” Laylan Connelly, Orange County Register, December 12, 2025.

Llanes reports from Colorado’s Keystone Resort, where the snowmaking guns have a built-in weather system that monitors temperature and relative humidity to optimize their performance. Citing Fassnacht, mentioned above, Llanes writes that “about 80% of the water used in snowmaking goes back into the watershed it came from,” but the amount of water used for snowmaking may rise if conditions get drier. The story also notes that snowmaking can be contentious:

“Telluride Resort is currently in a dispute with the town of Mountain Village over its water use, and a federal court recently dismissed a lawsuit from Purgatory, a resort near Durango, over accessing decades-old groundwater rights on Forest Service land.”

In Southern California, Connelly reports that the ski resorts situated between the desert and the Pacific Ocean have been investing millions of dollars in snowmaking and adopting more energy-efficient technologies that reduce diesel consumption. Big Bear Mountain Resort’s three ski areas “have 700 hydrants, 330 snow guns and 40 fans, with the ability to transform up to 6,000 gallons of water into snow every minute,” according to the story. “It’s a serious science,” Snow Summit’s Chris Winslow told Connelly. “It’s hard to make snow in Southern California. We literally would not be able to ski or ride in Southern California without snowmaking.”

As I noted in a prior post, a 2024 study found that snowmaking expenses run from $1,257 per acre in the Pacific Northwest to $2,673 per acre in the Northeast. That paper concluded that U.S. ski areas lost more than $5 billion from 2000 to 2019 due to fewer visits and higher snowmaking costs associated with climate change.

📊 5) Graphics show how U.S. snowfall is changing

As longtime readers know, I love data visualizations, so when I saw The Washington Post publish a series of maps and charts on snowfall trends and recent projections, it immediately caught my eye.

I’m a firm believer in copyright protections, so I won’t republish WaPo’s visuals here, but I’d encourage you to check out the excellent November 16 package by Ben Noll and Daniel Wolfe.

“A new analysis by The Washington Post found that swaths of the Plains, Midwest and East Coast have received much less snow than average over the past five winters — a trend that may continue this season, unless the polar vortex makes an early winter visit,” Noll and Wolfe write. “Around 70 percent of states in the contiguous U.S. have seen declining snowfall in recent winters, although parts of the West and some of the South have experienced more snow.”

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🌡️ 6) Sharp drop in a Rocky Mountain pika population

The American pika (Ochotona princeps), a small, squeaky, rabbit-like mammal, is considered an indicator species for climate change impacts on alpine ecosystems. A new study in Arctic, Antarctic, and Alpine Research finds that warming temperatures and changing snow conditions are stressing a population of pikas, which are commonly seen scurrying on talus slopes in the Rocky Mountains.

Pikas can only survive in a narrow temperature range. “Across most of its range, the pika requires snow cover for insulation during the cold season, as well as warm-season access to cool subsurface spaces—like those found in rock glaciers—where it can shed heat passively,” according to the paper.

The study is based on long-running survey data from the Niwot Ridge Long Term Ecological Research site, about 10 miles south of Colorado’s Rocky Mountain National Park. “The researchers discovered that the ‘recruitment’ of juveniles to this site seems to have plummeted since the 1980s,” according to a University of Colorado Boulder press release. “In other words, these populations are becoming dominated by older adults, with fewer juvenile pikas being born, or migrating in, to take their place.”

“Pikas don’t pant like a dog. They don’t sweat,” Chris Ray, lead author of the study and a research associate at the Institute of Arctic and Alpine Research, said in the release. “The only way they can release their metabolic heat is to get into a nice, cool space and just let it dissipate.”

The Colorado Sun’s Michael Booth wrote that the study offers “more proof that the ravages of warming from climate change threaten the pika’s very existence in the Rocky Mountains.”

🏔️ 7) Snow droughts and deluges affect Yosemite visitation

Snow droughts and snow deluges are the yin and yang of winter extremes.

At California’s Yosemite National Park, the lack or surplus of snow can shape tourism and recreation, according to a recent study in Scientific Reports. The researchers also analyzed how the park’s reservation system influences visitation.

“Changes in snow extremes can have important but as yet underexplored impacts on the 1.2-trillion dollar outdoor recreation industry, impacting essential ecosystem services,” the researchers write. “Climate change extremes and associated hazards limit and enable access in different ways: snowpack from extreme wet years can prolong road closures at higher elevations, while extreme snow drought enables early season access.”

The study found that “annual use levels are influenced more by managed access than by climate extremes.” The authors conclude that their findings “suggest that appropriately managed reservation systems are an essential tool for managing recreation resources in a changing climate.”

If you’d like to learn more about snow droughts and deluges, check out my conversations with scientists who study them:

💧 8) Tibetan Plateau snow droughts impact water supply for 1.5 billion people

Beyond affecting outdoor recreation, snow droughts can also pose a profound threat to the people who rely on snowmelt for their water supply.

A recent paper analyzes the cascading effects of snow droughts across the Tibetan Plateau, the headwaters for 10 major rivers—including the Yangtze, Indus, and Ganges—that provide water to around 1.5 billion people downstream.

“Escalating impacts of snow droughts have critically threatened hydrological stability and socioeconomic resilience on the Tibetan Plateau, Asia’s alpine water tower,” the researchers write in Communications Earth & Environment.

Analyzing data from 1979 to 2022, the scientists found “significant increases in severity” for both “warm” snow droughts (caused by a shift from snow to rain and accelerated melting) and “dry” snow droughts (caused by a lack of cold-season precipitation).

The study concluded that snow droughts are not only imperiling the water supply—they’re also transforming the region’s hydrologic cycle and worsening other climate extremes, such as hot/dry spells and hot/wet periods. Snow droughts can influence the Asian monsoon, alter soil moisture levels, and reduce the land surface's reflectivity (albedo).

The Tibetan Plateau is so critical to the planet’s cryosphere and climate that it’s often called the “Third Pole.” Temperatures there are warming at roughly twice the global average rate.

❄️ 9) The State of the Cryosphere report

It’s not an uplifting read, but the State of the Cryosphere 2025 report offers a solid synthesis of scientific research on Earth’s frozen places.

“Current unambitious climate commitments, leading the world to well over 2°C of warming, spell disaster for billions of people from global ice loss, but that damage can still be prevented,” according to the International Cryosphere Climate Initiative, which produced the report. “The European Alps, Scandinavia, North American Rockies and Iceland would lose at least half their ice at or below sustained global temperatures of 1°C, and nearly all ice at 2°C.”

Citing a 2025 study, the report also warns that “snowpack in the Western United States, a critical water source for 100 million people, is set to lose 34% of its seasonal volume by 2100.”

😱 10) Snowpack update

In my previous post, I wrote about the grim status of the West’s skimpy snowpack. I’m sorry to report that the situation remains bleak across most of the region.

The December 16 map below shows the snow water equivalent readings at individual monitoring sites. All those red dots mean this measure of the snowpack’s water content is below 50% of the median (1991–2020); orange dots indicate 50% to 69%.

In a December 11 update, the federal National Integrated Drought Information System (NIDIS) reported that December 7 snow cover across the West was the lowest for that date in the satellite record since 2001.

“Nearly every major river basin in the West experienced a November among the top 5 warmest on record,” NIDIS said, adding that “much warmer-than-normal temperatures caused precipitation to fall as rain instead of snow across many basins, leading to snow drought despite wetter-than-normal conditions across most of the West.”

⏸️ Programming note: With winter break approaching, I’ll be taking some time off and shifting from writing about snow to playing in it on a road trip to Colorado ski resorts. I’ll resume publishing after the new year.

In the meantime, you can keep up with my alpine exploits on the snow.news Instagram, Facebook, and Threads accounts, where I’ve started sharing more of my photos of snow, skiing, and snowboarding.

Happy Holidays!

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The American West sure could use some snow.

We’re just over two months into the water year, which began October 1, so there’s plenty of time to catch up. But it’s been a dismal start for the snowpack across nearly the entire region.

As shown in the map above, only Arizona had a statewide snowpack above the long-term median on December 4, while seven of the 11 contiguous Western states had readings below 50% of normal.

It’s a different story for overall precipitation, which includes both rain and snow. The map below shows that all Western states except Oregon were near or above the 30-year median for precipitation, with Arizona at nearly double the normal level since October 1.

In short, it’s been a decent water year thus far for moisture in the West, but not for snow, with warmer temperatures causing raindrops to fall instead of snowflakes.

How warm has it been this fall? Check out this map that climatologist Brian Brettschneider posted on Bluesky:

The rainy conditions weren’t helpful for launching the ski season—some Western resorts delayed their openings—but the moisture at least improved drought conditions in some places.

The chart below shows the percentile rankings for the statewide snow water equivalent, a measure of the snowpack’s water content. Those “0” readings for Idaho and Wyoming mean the snowpack in these states was essentially at record-low levels for December 4 when measured against the 1991-2020 period of record.1

Drilling down into the West, the map below shows basin-by-basin figures for snow water equivalent on December 3.

If you’d like to learn more about online resources for monitoring the snowpack, I published a cheat sheet last year that provides links to helpful websites and explains the various methods used for tracking snow water equivalent:

SnowSlang: N is for “nor’easter”

This newsletter focuses on the American West, but I spent my first quarter-century of life in New York, Connecticut, and Washington, D.C., so my early exposure to snowfall was shaped by East Coast weather patterns.

One of my strongest childhood memories of snow was formed in 1978, when I was eight years old, and a so-called nor’easter storm buried much of New England and the New York metropolitan area. The Blizzard of 1978, as it became known, dumped several feet of snow, killed about 100 people, and paralyzed the region for days, according to the National Weather Service.

A nor’easter is a strong low-pressure system in the middle latitudes of the western North Atlantic Ocean that can deliver hurricane-force winds and deluges of precipitation, both liquid and frozen. Technically, a nor’easter is a type of extratropical cyclone (hurricanes are tropical cyclones that form at lower latitudes).

The name “nor’easter” stems from the typical northeasterly winds that are experienced along the coast when cold air, often originating in Canada, collides with warm and wet air over the Atlantic, as shown in the graphic below.

When a frigid Arctic air mass crashes into the toasty Gulf Stream current, the atmosphere can get a little crazy, whipping up blizzards, flooding, and coastal erosion. More from the National Weather Service:

Some well known Nor’easters include the notorious Blizzard of 1888, the “Ash Wednesday” storm of March 1962, the New England Blizzard of February 1978, the March 1993 “Superstorm” and the recent Boston snowstorms of January and February 2015. Past Nor’easters have been responsible for billions of dollars in damage, severe economic, transportation and human disruption, and in some cases, disastrous coastal flooding.

In a previous post, I wrote about bomb cyclones, which are rapidly strengthening extratropical cyclones. They’re defined by a precipitous drop in atmospheric pressure of at least 24 millibars in 24 hours, so some nor’easters meet the threshold and count as bomb cyclones. But many nor’easters develop more slowly and don’t attain bombogenesis, a term that I adore!

After forming, a nor’easter usually travels northeastward along the East Coast before moving out to sea. Winter incarnations are the best-known and most intense nor’easters, but the storm pattern can actually form year-round.

Since 1940, the strongest nor’easters have been getting stronger in both their maximum wind speeds and hourly precipitation rates, according to a July 2025 study in the Proceedings of the National Academy of Sciences. After studying 900 nor’easters, the researchers concluded that about 10.6 such storms happen each year.

Overall, extratropical cyclones are expected to decline in frequency due to climate change as rapid Arctic warming reduces the pole-to-equator temperature gradient. But there’s been an intensification of strong nor’easters “due to increased storm moisture, fueled by warmer ocean temperatures,” according to the study.

Because nor’easters can menace the heavily populated I-95 corridor, from Boston to Washington, D.C., the threat of their rising intensity “portends prospects of paralyzing snowfalls, dangerous storm surges, and episodic cold extremes, underscoring the urgent need for coordinated efforts to assess and mitigate the devastating impacts of future such storms,” the researchers write.

By the way, it turns out there’s something called a nor’wester, which signifies both a cloud formation in New Zealand and spring storminess in India and Bangladesh.

When I searched for so’easter, all I came up with were sites about Easter.

But a sou’wester is what you might see on the head of someone fishing for crabs or lobsters during a nor’easter. The Oxford English Dictionary defines it as “a large waterproof hat or cap, originally made of oilskin, with a broad rim, worn esp. at sea to protect the head and neck during rough or wet weather.” Wikipedia says the name stems from “the southwesterly wind which brings warm air from the tropics to the British Isles, often bringing rain as it cools over the sea.”

A quick note about paid subscriptions

I recently activated a paid subscription option for snow.news. Don’t worry—everything I publish remains free. I’m not putting anything behind a paywall or changing the content you receive.

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If you’d like to pitch in and sustain my independent snow journalism, it’s $6/month or $60/year.

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Thanks, as always, for reading and sharing snow.news. Your support—whether free or paid—helps keep this work going, and I’m deeply grateful.

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Snow, ice, and frigid temperatures have created both threats and opportunities for warriors throughout the ages.

Winter weather can become an enemy or an ally—claiming lives and severing supply lines, or concealing offensives and leveling the battlefield.

In Part 1 of this series, I examined how frozen water and bitter cold shaped six pivotal military conflicts—from George Washington’s 1776 crossing of the Delaware River to the daring 1943 commando raid on Hitler’s nuclear weapons program in Norway.

In this post, I finish my survey of key battles in which the cryosphere played a leading role. Although snow.news focuses on topics like the water supply and winter sports, I can’t tell the full story of snow without digging into its darker history of tragedy and misery.

Toward the end, I take the liberty of looking into the future. These scenarios aren’t based on séances with the ghost of Henry Kissinger but on decades of compulsive news consumption—habits forged during my upbringing as one of the Cold War kids who grew up watching The Day After and WarGames.

As in Part 1, I’ve listed resources for further reading; some of the books are still on my docket, but anything marked with a ✅ means I’ve read the source and recommend it.

7) The 10th Mountain Division and America’s ski industry

Many books have been written about the “ski troopers” who endured grueling alpine training around Colorado’s Camp Hale—now a national monument near Vail. Veterans of the 10th Mountain Division include many founders and leaders of the American ski industry: Pete Seibert (Vail), Friedl Pfeifer (Aspen), Alf Engen (Alta), Minnie Dole (National Ski Patrol), and dozens more. Some 70 U.S. ski resorts have ties to the 10th Mountain Division.

Even before the United States entered World War II in 1941, some military planners recognized that the nation was sorely lacking in manpower, expertise, and equipment for fighting in mountainous or snowy environments. By contrast, the Germans had their elite Gebirgsjäger—highly trained alpine troops with specialized gear and extensive high-altitude experience.

To remedy the situation, and with much press fanfare, the U.S. Army created a mountain training center at Camp Hale. It drew some of the world’s leading skiers, alpinists, and mountaineers, including refugees from nations already overrun by the Nazis.

The video below is a propaganda film produced by Warner Brothers in 1943, complete with fake battles and singing troops.

Ironically, much of the snow-related training and equipment ended up being of limited use. When the troops were sent to Europe in 1945 to take part in the invasion of Italy, the fighting was in the lower-elevation Apennines, rather than the snowy Alps. Still, the battles were fierce, bloody, and heroic; as historic accounts attest, it was like the opening to Saving Private Ryan, only set in the mountains. One of the most celebrated conflicts was the taking of Riva Ridge—now the name of a legendary trail at Vail that drops 3,000 vertical feet.

The fancy alpine gear developed at Camp Hale and elsewhere never wound up reaching the theater of combat because of military snafus and shifting priorities. After the Allies conquered the Apennines, the Germans gave up in Italy, obviating the need to invade the Alps in a potential repeat of “The White War,” the World War I battle I wrote about in Part 1.

📖 Learn more:

✅ The Last Ridge: The Epic Story of America’s First Mountain Soldiers and the Assault on Hitler’s Europe, McKay Jenkins, 2021.

✅ The Winter Army: The World War II Odyssey of the 10th Mountain Division, America’s Elite Alpine Warriors, Maurice Isserman, 2019.

8) The Eastern Front: Germans vs. Soviets in World War II

As I noted in my earlier post, Napoleon’s attempt to march east and conquer Russia in 1812 ended in catastrophe. But that didn’t stop Hitler from trying the same thing in World War II, leading to the deaths of more than 20 million Soviets, plus millions of Germans on the Eastern Front.

In the deadliest theater of World War II, the mass of casualties is almost impossible to fathom. During the conflict, for example, the Germans laid siege to Leningrad (now Saint Petersburg) for 872 days, so the carnage occurred year-round, but the suffering was particularly brutal during the Russian winter.

The Battle of Stalingrad remains one of the bloodiest fights in world history, which is saying something. Hitler’s attempt in 1942 to capture the namesake city of the Soviet leader led to the deaths of around 2 million combatants and civilians. When winter arrived, the Soviets leveraged their familiarity with cold-weather combat to encircle the German 6th Army. Poorly equipped for the cold, the Germans froze, starved, fell ill, and failed to receive succor from the Luftwaffe’s promised airlift due to the challenging weather and Soviet anti-aircraft fire.

The Soviet victory at Stalingrad marked a key inflection point in World War II and helped turn the tide against the Nazis.

📖 Learn more:

✅ Russia’s War: A History of the Soviet Effort: 1941-1945. Richard Overy, 2022.

✅ The Eastern Front: The German War against the Soviet Union. United States Holocaust Memorial Museum.

When Titans Clashed: How the Red Army Stopped Hitler, David M. Glantz and Jonathan M. House, 2022.

9) The Battle of the Bulge and the Winter Offensive of 1944-1945

The Allied invasion of Normandy in June 1944 was the beginning of the end for the Nazi empire, but Hitler wouldn’t go down easily.

In December 1944, the Germans launched a surprise winter attack against weakly defended Allied positions in the Ardennes Forest of Belgium and Luxembourg. The Nazis’ goal was audacious: pierce the Allied lines, capture Antwerp, and force a potential negotiated peace on the Western Front. The Germans’ last-gasp gambit used winter weather to their advantage and thrust their forces deep into Allied-controlled territory, creating a “bulge” in the hard-fought line.

During one of Europe’s coldest winters in decades, the Nazi and Allied troops fought viciously in what would become the largest, bloodiest battle for American forces in the entire war. Some 600,000 American troops took part in the conflict, with around 90,000 killed, wounded, captured, or missing.

The extreme cold and snowy weather caused weapons to jam and forced vehicles to freeze up, limiting both sides’ ability to fight and travel overland. In the skies above, storms and poor visibility hampered Allied air operations. Countless soldiers suffered from frostbite, hypothermia, and trench foot, a malady first recognized in World War I, in which persistent exposure to cold, damp, and unsanitary conditions caused ill-equipped soldiers to suffer severe tissue damage in their lower extremities.

Ultimately, clearing weather allowed Allied air superiority to reassert itself. General George Patton’s Third Army led a successful charge against the Germans, who were eventually pushed back to their starting positions, badly weakened by the encounter.

On the Eastern Front, snow and cold weather would also play a defining role in the Soviets’ winter offensive against the Germans in early 1945, which sounded the death knell for the Nazis. In Eastern Europe, the muddy times of rasputitsa (season of bad roads) can slow or obstruct travel, even today, but during the frigid winter, the roads iced over, which helped the superior forces of the Soviets to quickly gain territory. As with George Washington’s charge across the Delaware River, the Soviet attack during the depths of winter caught the Germans by surprise.

By the end of April 1945, as Soviet forces were descending upon Berlin, Hitler gave up all hope and committed suicide in his bunker. Germany surrendered about a week later.

📖 Learn more:

✅ The Longest Winter: The Battle of the Bulge and the Epic Story of World War II’s Most Decorated Platoon, Alex Kershaw, 2007.

10) The Korean War and the Battle of the Chosin Reservoir

It’s been more than seven decades since the Korean War (1950-1953), yet the United States remains locked in a tense military standoff on the divided peninsula.

In June 1950, North Korea, backed by the Soviets, invaded South Korea and quickly captured its capital, Seoul. In response, the United Nations and the United States, led by General Douglas MacArthur, stepped in to defend the South Koreans. After a dramatic amphibious assault at Inchon in September, the U.N. and U.S. forces surged northward toward the Chinese border. At the same time, China began secretly inserting hundreds of thousands of troops into North Korea.

MacArthur underestimated the Chinese, who in November surrounded tens of thousands of troops as temperatures plunged around Chosin Reservoir. Outnumbered nearly four to one, the U.S. Marines and other soldiers had only one option: escape by fighting their way south to the port of Hungnam. The frigid conditions claimed innumerable casualties on both sides in what would become immortalized as the “Battle of the Frozen Chosin.” Temperatures dropped to minus 30 to 40 degrees Fahrenheit during the 17-day battle, causing 8,000 cases of frostbite on the U.S. side.

The Marines, later known as the “Chosin Few,” eventually reached Hungnam, where one of the largest amphibious evacuations in U.S. history unfolded. The breakout succeeded, but the Chinese soon reclaimed the North Korean territory. The war ground into a bloody stalemate that led to the division of the peninsula near the 38th Parallel, a fortified border that still exists today.

📖 Learn more:

✅ On Desperate Ground: The Epic Story of Chosin Reservoir—the Greatest Battle of the Korean War, Hampton Sides, 2019.

✅ The Korean War Battle of Chosin, How Military Medics Saved the ‘Chosin Frozen,’ Janet Aker, health.mil, 2023.

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11) Afghanistan’s “fighting season” in the Graveyard of Empires

Since 1776, our nation has fought many wars, but none were as long as the conflict in Afghanistan, which lasted nearly 20 years from 2001 to 2021, killed more than 2,400 U.S. service members, injured tens of thousands more, and cost trillions of dollars.

When U.S. forces finally withdrew, the Taliban swept back into power—an outcome that echoed the fates of earlier foreign armies that tried to impose their will on the region.

The Soviets invaded Afghanistan in 1979, attempting to prop up a faltering communist government. But their decade-long occupation proved ruinously expensive in blood and treasure, contributing to the eventual collapse of the USSR. After the Soviet withdrawal, Afghanistan descended into civil war. By 1996, the Taliban seized control of the country.

Long before the Cold War, the British Empire struggled to subdue Afghanistan in the 19th and early 20th centuries. During an infamous winter retreat from Kabul in 1842, roughly 16,000 troops and civilians tried to flee through snow-covered passes to Jalalabad; only one European, Dr. William Brydon, arrived safely, with the rest either captured or killed by the elements, starvation, and ambushes.

These accumulated military disasters gave Afghanistan its enduring moniker: the “Graveyard of Empires.”

Geography and the winter weather help explain why. Practiced in guerrilla warfare and insurgency, Afghan fighters have repeatedly outlasted and exhausted armies trying to invade and conquer the notoriously treacherous terrain. The Hindu Kush mountain range, which dominates parts of the country, features harsh winters and a maze of glacially carved landscapes that have long confounded warriors.

Even in the 21st century, Afghanistan had a “fighting season” shaped largely by snow cover: when mountain passes closed, vast swaths of the country became inaccessible, creating a meteorological ceasefire until the so-called “spring offensive” that we used to hear about regularly in the news.

📖 Learn more:

The American War in Afghanistan: A History, Carter Malkasian, 2023.

12) The Russo-Ukrainian War (2022-today)

Russia invaded Ukraine in February 2022, and since then, the war has transcended multiple cycles of all four seasons, becoming Europe’s bloodiest conflict since World War II. As in earlier European wars, wintry weather has been a key element of the fighting, posing obstacles to transportation and creating a lethal threat beyond bullets and bombs.

After Ukrainian forces launched counteroffensives in the fall of 2022, the Russians struck back with a winter campaign that sought to capture the remainder of the province of Donetsk Oblast. Losses were heavy on both sides, but the Russians failed to gain much ground.

Compared to the armies commanded by Napoleon, Stalin, and Hitler, today’s warriors have far more advanced clothing, equipment, and weaponry. But winter’s old enemies persist: diesel fuel and lubricants still thicken in frigid weather, rifles can still seize up due to frozen condensation, and the human body still remains vulnerable to cold, wet weather.

Drones have become a defining feature of the battlespace, but as any drone pilot (including me) will tell you, cold weather shortens battery life, reduces flight time, and limits drones’ effectiveness.

For Ukrainian civilians, power outages during the winter have posed mortal dangers, and this targeting of energy infrastructure has been an explicit Russian strategy.

📖 Learn more:

✅ Ukraine and Russia claim to be prepared for extremes of winter warfare—here’s what they face, Marina Miron, The Conversation, 2023.

The Russo-Ukrainian War: The Return of History, Serhii Plokhy, 2023.

Invasion: The Inside Story of Russia’s Bloody War and Ukraine’s Fight for Survival, Luke Harding, 2022.

13) Opening up the Arctic (today)

No one’s fighting over the Arctic—yet—but the region is shaping up as a pivotal arena for potential future conflicts as melting sea ice makes it more navigable and strategically valuable. President Donald Trump’s aspiration to buy Greenland is one obvious sign of the Arctic’s growing geopolitical profile.

Long before human-caused climate change began transforming the region, the Arctic was a crucial chessboard in the Cold War, as both the United States and the Soviet Union deployed nuclear submarines to prowl beneath the ice and occasionally surface. Today, both nations remain rivals, the cat-and-mouse game continues, and the Arctic is still key terrain for early-warning systems because the shortest route for intercontinental ballistic missiles flying between the United States and Russia runs over the North Pole.

As the ice melts, new sea lanes are opening up, such as the Northwest Passage through Canada’s Arctic and the Northern Sea Route off Russia’s Siberian coast. These potential new shipping routes could become chokepoints and flashpoints, similar to today’s Strait of Hormuz off the Iranian coast, with big implications for global trade and military operations.

The Arctic region is also thought to hold vast reserves of fossil fuels and critical minerals that will become easier to exploit as the ice recedes. Consequently, many nations have been stepping up their capacity to explore for and defend Arctic resources, using assets such as icebreakers and military bases.

📖 Learn more:

✅ In the Arctic, American commandos game out a great-power war, Alex Horton and Salwan Georges, The Washington Post, 4/11/24.

✅ Hiding an Army at the Top of the World, Liam Denning and Louie Palu, Bloomberg Opinion, 6/4/23.

✅ See How Russia Is Winning the Race to Dominate the Arctic, Daniel Kiss, Thomas Grove, Vipal Monga, Austin Ramzy, and Roque Ruiz, The Wall Street Journal, 2/3/25.

2026 and beyond: Can we avoid a nuclear winter?

Talk about ending on a downer. Sorry, folks, but I wouldn’t be true to myself or foreign policy realism without venturing into this awful territory.

Yes, I’m scared and depressed about climate change. But part of me fears we’re going to leapfrog past the steady baking of the planet and plunge instead into a thermonuclear exchange that fades to black with a frigid nuclear winter threatening to extinguish life around the planet.

If you’re not familiar with the concept, nuclear winter is the term scientists coined decades ago to describe the cataclysmic aftermath of a nuclear war. The explosions and radiation would be calamitous enough, but the real killer would be the fires and their impact on the climate. Enough soot could be hurled into the atmosphere to blot out the sun for years and cause the Earth to descend into an apocalypse akin to a mini ice age. With enough cooling, billions could die from starvation. Ecosystems that evolved over millions of years could collapse in a geologic instant.

Could it really happen? Let’s hope not, but plenty of scientific studies have simulated the possibility. Some nuclear policy experts argue that our unstable world has never been closer to nuclear war than we are right now (see, for example, recent in-depth editorial projects by The New York Times and The Washington Post).

What are some doomsday scenarios for World War III and the onset of a nuclear winter? The scary thing is that it takes just one pathway, and there are plenty to choose from, especially since our government allows the president to unilaterally launch our nuclear weaponry within minutes in response to threats, both real and perceived (the new Netflix movie, A House of Dynamite, dramatizes this unthinkable decision). Other nuclear-armed nations are also on a hair-trigger.

Let me offer, in descending order of probability, my list of worries, each of which could set off a global chain reaction that is accelerated by AI-fueled disinformation:

• Warning systems go haywire because of a false alarm, accident, or sabotage

• China finally makes its move on Taiwan or in the South China Sea

• Russia’s war in Ukraine spirals out of control and pulls in NATO

• India and Pakistan escalate their long-simmering conflict over Kashmir

• North Korea’s despot decides to unleash his hard-won nuclear arsenal

• Israel and Iran resume hostilities and cross the nuclear threshold

An all-out nuclear exchange could mean Armageddon and the end of civilization as we know it, though most experts think the total extinction of the human species is unlikely. But even a smaller-scale, regional nuclear conflict could upend the Earth’s climate, causing worldwide death and destruction.

📖 Learn more:

✅ A Path Where No Man Thought: Nuclear Winter and the End of the Arms Race, Carl Sagan and Richard Turco, 1990.

✅ Nuclear War: A Scenario, Annie Jacobsen, 2024.

✅ 2034: A Novel of the Next World War, Elliot Ackerman and James Stavridis, 2021.

A Cold War kid in the 21st century

My head is full of geopolitical scenarios that could snowball into a nuclear winter. Writing this series forced me to revisit the Cold War obsessions that first gripped me as a teenager. One of the reasons I love snow and skiing so much is that they extract me from the mental winters I sometimes drift into.

I used to think about this stuff constantly. I entered Yale in 1988 as a hawkish fan of Ronald Reagan, fascinated with the intersection between game theory and nuclear strategy. One of my favorite books in high school wasn’t The Catcher in the Rye or To Kill a Mockingbird—it was Yale political scientist Paul Bracken’s The Command and Control of Nuclear Forces.

In college, I took sociologist Charles Perrow’s course on catastrophes and the inevitability of “normal accidents” in complex systems—a prospect that still haunts me. I planned to enroll in political scientist H. Bradford Westerfield’s famous course on intelligence and espionage, known to students as “Spies and Lies” (former Vice President Dick Cheney repeatedly said Westerfield’s tutelage in New Haven shaped his hard-line approach to foreign affairs).

But then the Cold War ended—or so we thought. Some very serious people were writing about the “end of history,” so I migrated to other topics, eventually settling on urban poverty. The liberal arts education at Yale shifted my politics, so upon graduating, I worked as a research assistant at the Urban Institute, a left-of-center think tank, before immersing myself in water and environmental issues in the American West.

All this is to say that I was weaned on a cynical, realpolitik view of foreign policy, which was colored by Eastern European, Jewish roots that made me treat holocausts and worst-case scenarios as tangible fears rather than academic abstractions.

The conservative economist and social theorist Thomas Sowell distinguished between constrained and unconstrained visions of human nature. The constrained view sees people as basically selfish, tribal, myopic, and stubbornly resistant to social engineering, however well-meaning. The unconstrained view holds that humans are more malleable and capable of evolving beyond their baser instincts to build a more harmonious world.

After decades spent in left-leaning circles—academia, journalism, environmental nonprofits—I have to admit that, when it comes to foreign affairs, I still find myself in the skeptical, constrained camp, retaining a jaundiced suspicion of our capacity to be angels.

I’m neither proud nor ashamed to be so jaded, so worried about a nuclear winter, or so sour about our prospects. It’s not a comfortable outlook. But it’s also something I can’t ignore.

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I’m excited to share this story I wrote for The Water Desk, an independent journalism initiative at the University of Colorado Boulder that I co-direct.

As the American West warms due to climate change, wildfires are increasingly burning in higher-elevation mountains, charring the watersheds where the region’s vital snowpack accumulates.

A new study has found that in the immediate aftermath of fires across the region, the snowpack disappears earlier in burned areas. This change can threaten forest health and affect the downstream farms, cities and species that rely on the snowpack for their water, according to other research.

Scientists who study the effects of wildfires on the snowpack and streamflows are finding that the story is complex and nuanced. The impacts can vary greatly across the West’s diverse ecosystems and topography. Plus, each wildfire burns differently, so the severity of the blaze is another critical factor.

While streamflow volume typically increases after a wildfire, the peak flows come earlier in the season, and the water may be clogged with sediment that can harm wildlife and water infrastructure.

The new study, published in the September 17 issue of Science Advances, used satellite data to track when the snowpack disappeared each season and examined how that timing changed after a fire burned through forests. The research also concluded that warming temperatures due to climate change will further accelerate post-fire melting.

In the first year after a fire, the researchers found that under average winter conditions, snow melts earlier in 99% of the snow zone. “Postfire snow cover loss is more extreme in relatively low-elevation, warm environments compared to that in high-elevation, cold regions,” wrote the researchers from the Colorado School of Mines and the University of Colorado Boulder’s Institute of Arctic and Alpine Research.

The loss of the forest canopy due to a fire can actually increase snow accumulation on the ground below because scorched trees that are missing branches and needles intercept fewer falling snowflakes. But opening up the canopy changes the flow of energy in the forest by exposing the underlying snowpack to more solar radiation that can melt the snow.

Wildfires also cause soot and darkened debris to fall on the snowpack, which reduces its reflectivity, allows more heat to be absorbed and leads to quicker melting. Burned forests are also more susceptible to wind, which can further erode the snowpack.

“It’s basically just a big energy balance puzzle, but it seems like that increase in sunlight and decrease in the reflectivity of the snow are both leading to (an) earlier snow disappearance date,” said lead author Arielle Koshkin, a doctoral candidate in hydrologic science and engineering at the Colorado School of Mines. “Even if we do see more snowfall in the forest, it’s not overriding those energy balance changes.”

The study notes that previous research has found that the acreage of Western forests burned in the seasonal snow zone increased by up to 9% annually between 1984 and 2017, with the biggest rise in burned area occurring above an elevation of 2,500 meters (8,202 feet).

“Fire is burning higher and higher in elevation, which increases this overlap between where burned forests are and where it snows,” Koshkin said.

Stephanie Kampf, a professor of watershed science at Colorado State University who wasn’t involved in the study, said the findings are “pretty consistent with prior research” showing that snow disappears earlier after a fire and that lower-elevation locations with more “transitional” snowpacks are more vulnerable. “This study shows it really nicely with a big dataset,” Kampf said.

Climate change speeds up melting

Looking ahead, the authors project that post-fire melting will accelerate further as the West gets hotter due to rising atmospheric levels of greenhouse gases. If warming increases by 2 degrees Celsius—something that’s possible by the middle of the 21st century under some emissions scenarios—“73% of the snow zone would experience more extreme earlier postfire snowmelt compared to historically average conditions,” according to the paper.

“Under two degrees (Celsius) warming, the areas that already showed large changes are going to show even larger changes,” Koshkin said. “That warming is going to really have (an) impact on those warmer snow climates. So think maritime, Cascades, Sierras, comparative to the higher, colder, Rocky Mountain West.”

Previous research has also looked at what happens to the snowpack after a fire and found that the snow disappearance date moves up four to 23 days. Some of those studies have used ground-based observations, but the papers typically focused on one to three fires. Other research has examined snowpack readings from the automated SNOTEL network, but those snow sensors are usually placed in gaps in the forest canopy and may not capture the diversity of the West’s landscapes.

This new study relies on images captured by the MODIS instruments aboard two satellites to provide a Westwide look at wildfire’s effects. Currently, satellites cannot measure the water content of the snowpack, known as the snow water equivalent. But repeated satellite imagery can detect whether snow is present on the ground, allowing researchers to measure when the snowpack disappears during the year.

“I was really interested in seeing if we could leverage remote sensing to look at it on a pixel-by-pixel scale across the whole Western United States to really try to understand, are we seeing the same responses in the Pacific Northwest as in Colorado?” Koshkin said.

Each pixel in the MODIS satellite imagery represents a square on the ground with 500-meter (1,640-foot) edges. That’s a somewhat coarse resolution for measuring the snowpack, which can vary dramatically over very short distances, but the satellites provide daily or near-daily coverage.

While satellite data offers broad coverage of the region, it has significant limitations.

“The satellites can’t really peek underneath the forest canopy,” said Anne Nolin, a professor in the geography department at the University of Nevada, Reno, who wasn’t involved in the study. (Koshkin is a former student of Nolin’s.) “The other issue is that the satellite data can’t measure snow at times when there’s rain occurring or anytime there’s cloudiness. And so if you have a rain-on-snow event that’s changing your snowpack, which we’re having more and more, and which we would anticipate to occur more frequently, then you’re probably missing short-term changes in snowpack.”

Nolin said that the satellite-based estimates of the snowpack were “likely to be inaccurate in places where you have remaining forest, and especially in low-elevation snow zones and under warmer winter conditions.” That’s because previous studies have found that in warmer forests, the snow melts off under the canopy early, but it’s retained in the gaps between the trees, so the algorithm used to process the satellite imagery can overestimate the amount of snow in the pixel. “There’s less snow there than you think,” Nolin said.

Stark regional differences

Elevation, temperature, burn severity, vegetation type and the amount of incoming solar radiation are among the drivers explaining when the snow disappears. The variability of these factors across the West may help explain why previous studies have found such a wide range in the timing of the snow disappearance date.

“Everywhere we looked was disappearing earlier, but there were these kind of hotspots that disappeared way earlier,” Koshkin said. “I think the disruption in streamflow from these earlier melting-out pixels will be much more significant in Oregon, Washington and California.”

Wildfires had the biggest effect on the snowpack during the first five years after the blaze. In the first year after a fire, the snow disappearance date advanced by an average of 3.3 days. That might not sound like much, but the figure is just an average for the entire West—in some parts of Northern California and Oregon, the snow disappeared up to two weeks earlier.

Over time, the effects of fire declined. Ten winters after a blaze, for example, the average snow disappearance date moved up by less than a day.

While the advance of the snow disappearance date was most pronounced at lower elevations, the snowpack actually persisted slightly longer in some burned areas in Colorado and Utah, where the colder temperatures at higher elevations can insulate the snowpack from changes.

The finding that some higher elevation locations had a later snow disappearance date “would definitely be something to explore because everything that we know so far suggests that snow disappearance should be earlier after a fire,” Kampf said.

Higher elevations may be less vulnerable to an early disappearance of the snowpack due to late-season storms. “Here in Colorado,” Kampf said, “we get a fair amount of spring snow, and so that’s one of the reasons why we’re not as sensitive because sometimes that snow just comes in May and it resets everything and you don’t see the big change in snow disappearance date.”

Another factor in explaining the regional differences is the West’s diversity of vegetation.

“The forests are different in places that are colder, so you have different tree species and different densities of forest and different ecosystems in general,” Nolin said. “The northern tier of states and the high country—that’s where you would be probably seeing the least amount of change. It doesn’t mean, though, that you have the least amount of fire because some of these places, especially in places like Idaho and Washington state, have significant amount of fire, and there’s some interesting studies that have shown earlier snowmelt in those locations as well.”

How wildfires change streamflow

Previous research has found that wildfires can significantly alter the timing and magnitude of runoff in burned watersheds, but scientists are still unraveling the details.

“If you burn down the forest, you don’t have as many trees that are using that water,” Nolin said. “You probably expect the streamflow to be earlier because the snow’s melting off earlier.”

Fires can not only kill trees and ground cover that would absorb water—they can also eliminate organic material in the soil, which causes the ground to become more water repellent and makes the snowmelt more likely to run off into streams.

A 2022 study that examined 72 forested basins that burned across the West found that average streamflow was significantly higher after a wildfire for an average of six years. The increase in streamflow was greater in areas where the extent of wildfire was larger. That study also found that the annual acreage burned by wildfires in the West skyrocketed by more than 1,100% from 1984 to 2020.

Kampf said more research is needed to understand how streamflow changes after a fire. “We don’t have all those interactions figured out yet, but there have been some studies that have shown that streamflow actually decreases after fire,” Kampf said. “We certainly know it will affect streamflow timing, but the amount of streamflow we’re less sure.”

Fire intensity is one key determinant of subsequent streamflow.

“If the forest is totally torched, then the increased solar radiation that’s coming into the snowpack is going to have a much bigger effect than if the trees still have live branches on them,” Kampf said. “Similarly, when you get down to the soil, if the soil is totally burned to a crisp, then its infiltration impacts will be much greater than if a lot of the litter and other stuff in the soil is still there.”

Nolin said she would have liked to see the authors distinguish between areas of high, moderate and low burn intensity.

“When you see photographs of burned areas, we tend to show the photos that are most dramatic with just charred trunks that have (been) left behind, but in fact, most fires are mainly low to moderate burn severity that maintain the forest canopy,” Nolin said. “To not distinguish between different burn severities and to indicate that it’s all about the canopy being burned off and all of this carbon shedding on the snow—I think that stretches the results.”

The speed of vegetation recovery also shapes how the snowpack and streamflows respond to wildfire over time.

“If it’s a forest type where the vegetation can respond quickly and come back, that’s going to be a really different response than if the vegetation is slow to grow,” Kampf said. “Here in Colorado, we have some fires where it’s not coming back as forest at all, and where there are just no seedlings, and so we would expect the fire effect on snow to persist for a long time because we just don’t have trees coming back.”

The post-fire effects on streamflow tend to be localized, so it can be difficult to detect their effects on major river basins.

“Even though the fires we’ve been experiencing have been really large, they’re still not huge compared to the size of the watershed as a whole,” Kampf said. “If you looked at something like the Colorado River Basin, it might be hard to detect the fire effect on the flow because there’s such a huge area that’s contributing to that flow. So in terms of how water is managed in forecasting and dam operations, I don’t think we’re there yet in terms of knowing how to account for fire.”

A major worry for water managers is the threat of high-intensity fires burning through dense stands of forest in the watersheds above their systems.

“Those are places that water managers are concerned about because if the forest burns, then they experience problems with post-fire erosion and sedimentation and harms to water infrastructure, so it’s kind of a different side of the water management issue,” Kampf said.

Impacts on ecosystems

Besides posing challenges for water managers, wildfires can have profound effects on wildlife and forest health.

For aquatic ecosystems, “having a shift in the timing of when flow is coming in could also have an impact,” Kampf said, but “probably the greater impact is when that flow is bringing in with it a lot of sediments that are changing the habitat more profoundly.”

More rapid melting of the snowpack after a fire can also lead to a longer dry season for forests.

“If the snow disappears earlier, plants will start greening up sooner,” Kampf said. “If they’re not getting a lot of summer rain, they may find drier conditions later in the growing season that can stress plants.”

In addition to snow disappearing earlier due to fires, Nolin said the weather in November is getting drier. “If you have an earlier snow disappearance date and a later snowfall date, that dry season’s really getting quite a bit longer, and so it means that you have a decline in forest health and you also have an increase in the potential” for a longer fire season, Nolin said.

How burned ecosystems will respond to fire remains an open question as the climate continues to warm. In many parts of the West, decades have passed since flames swept through a forest, but trees have yet to return.

The burned trees may be centuries old, “and the climate was different than when those little seedlings sprouted and became the big trees that ultimately were involved in the fire,” Nolin said. “They grew initially under a different climate, and we don’t have that climate anymore, so we might see a lot more shrubs.”

Nolin said the paper “used a very simplistic approach to looking at future impacts on snow” by only examining what will happen under 2 degrees Celsius of warming. Climate change will also alter such factors as relative humidity and precipitation, so including these other effects “would’ve been more nuanced and perhaps a little more supportable,” Nolin said. She would have liked to see the results for various temperature increases up to 4 degrees Celsius, noting that mountains are warming faster due to climate change, and a key question is whether rain or snow will fall under warmer conditions.

“Just having a single temperature change to look at helps us understand the impacts of temperature, and that’s great, but there is a lot more to be done in this area,” Nolin said.

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The West’s snowpack season is off to an uneven start.

As shown in the map above, parts of the region are way above normal for snow water equivalent, a measure of the snowpack’s water content. But here in Colorado, which supplies water to 19 other states and Mexico,1 the situation has been bleak so far.

It’s still very early in the season, so these numbers are subject to change quickly and dramatically. The Natural Resources Conservation Service, which provides the data, says its snowpack website isn’t being updated during the federal shutdown, and the basin maps “are being retired and will no longer be updated or available.” The maps are, in fact, still available, yet I wonder about their accuracy (e.g., the zero reading in California).

The Colorado Avalanche Information Center reported on Instagram that last month was the driest October for Colorado in terms of snow water equivalent since the 2016-2017 season. Below is a map showing the unfortunate situation on November 5, which has me seeing red. 😡

“Although it’s not great for Colorado’s water resources, a lack of early-season snow could be beneficial for future snowpack stability,” the CAIC wrote. “When we have snowy Octobers with big storms—followed by breaks in snowfall—that layer of snow sits on the ground, faceting and turning into weak, cohesionless snow that is unable to support future loads.”

Here’s another look at Colorado’s abysmal snowpack from CAIC’s Facebook page:

A few ski resorts in Colorado (Arapahoe Basin, Keystone, and Winter Park) have opened up extremely limited terrain thanks to snowmaking, but in many places, it has been too warm to make fake snow.

Very long-range forecasts for snowfall are notoriously unreliable, but for what it’s worth, the map below shows the Climate Prediction Center’s broad-brush outlook for precipitation for the November-December-January period.

We’re currently in a La Niña pattern, which tends to make northern-tier states wetter and the Southwest drier in winter, although federal forecasters don’t expect La Niña to last very long.

SnowSlang: M is for “Milankovitch cycles”

For eons, our planet’s climate has been oscillating between extremes.

In “hothouse” or “greenhouse” periods, temperatures soared, snow and ice were scarce, and the oceans rose high enough to drown portions of the continents.

In “icehouse” periods, temperatures plunged and ice sheets expanded from the poles, locking up enough water to lower sea levels by hundreds of feet.

What’s behind these long-term shifts? On geological timescales of hundreds of millions of years, there are numerous causes, including plate tectonics, volcanic activity, and natural fluctuations in atmospheric levels of carbon dioxide.

But on shorter time scales—tens of thousands to hundreds of thousands of years—there’s another key factor in our ever-changing climate: the motion of the Earth itself.

In the early 20th century, Serbian mathematician Milutin Milankovitch calculated how three repeating patterns alter the amount of solar radiation reaching the Earth, thereby influencing the climate in somewhat predictable ways. Known as the Milankovitch cycles, these three drivers interact with one another and have led our planet to toggle between glacial and interglacial periods for millions of years during our current icehouse phase:

1. Eccentricity (~100,000-year cycle): Our orbit shifts from a nearly perfect circle to slightly more elliptical, which alters Earth’s distance to the sun and changes how sunlight is distributed between seasons and hemispheres. Eccentricity doesn’t make a big difference in the total sunlight that Earth receives, but its interaction with precession (described below) helps alter the climate.

2. Obliquity (~41,000 years): The tilt of Earth’s axis varies between about 22.1 and 24.5 degrees (we’re currently at 23.4 degrees). More tilt means more extreme seasons—hotter summers and colder winters—especially at high latitudes. Less tilt means more moderate seasonal differences.

3. Precession (~19,000–23,000 years): Like a spinning top, the planet wobbles on its axis, which alters when seasons occur relative to Earth’s orbital position. If, for example, the Northern Hemisphere’s summer occurs during the closest passage to the sun (perihelion), the hotter summers melt more snow/ice.

The NASA animation below illustrates how each of these cycles unfolds.

Over time, these changes in eccentricity, obliquity, and precession work in tandem to shape the climate, especially at high latitudes in the Northern Hemisphere. These regular cycles in Earth’s motion play a leading role in how much snow and ice persist from year to year. If summers are cool enough, winter snow doesn’t melt, ice sheets expand, and the increasing reflectivity (albedo) of the Earth’s surface causes further cooling in a feedback loop.

Some climate change skeptics have pointed to the Milankovitch cycles as a potential cause of the global warming we’re experiencing. But the science shows otherwise. Our current warming is playing out over decades to centuries, not tens of thousands to hundreds of thousands of years.

More from NASA:

Over the last 150 years, Milankovitch cycles have not changed the amount of solar energy absorbed by Earth very much. In fact, NASA satellite observations show that over the last 40 years, solar radiation has actually decreased somewhat . . .

. . . If Earth’s current warming was due to the Sun, scientists say we should expect temperatures in both the lower atmosphere (troposphere) and the next layer of the atmosphere, the stratosphere, to warm. Instead, observations from balloons and satellites show Earth’s surface and lower atmosphere have warmed but the stratosphere has cooled.

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In an earlier post, I outlined 10 reasons why snow is so important, including its impact on the water supply, biodiversity, farming, wildfires, winter sports, and the climate.

That list focused on snow as a beneficial resource that generates value—natural, economic, recreational, and aesthetic. These magical ice crystals can even make us feel warm and fuzzy.

Something I failed to cover: snow’s long-standing role as a mortal threat, terrifying obstacle, and destroyer of lives, especially in the realms of transportation and warfare.

As an inveterate worrier prone to catastrophizing and covering the doom-and-gloom beat, I sincerely regret the omission!

In this post—the first of a two-part series—I focus on warfare and begin to survey key armed conflicts in which snow and wintry weather have been pivotal. I’ll publish Part 2 soon.

Taking the long view, snow, ice, and frigid temperatures have played a leading role in military history because they have sometimes created insurmountable threats and barriers for manpower and material while setting the terms for key battles whose outcomes still resonate in today’s precarious balance of power.

The calendar says 2025, yet to me it feels a little like 1914 or 1939, as rivals clash, alliances crumble, citizens radicalize, climate change intensifies, economic inequalities widen, and digital technologies create a flood of disinformation.

Pardon me if this subject seems like a dark departure for an outdoorsy science writer and multimedia journalist fond of bluebird powder days, but I was once an aspiring nuclear strategist! This was during my hawkish teenage years in the 1980s at the height of the Cold War (more on that in Part 2).

I remain captivated by military history, one of the genres I read in my leisure. It’s also a subject that’s increasingly relevant in today’s dangerous, volatile world as the hegemony of the United States melts and the nation faces mounting—and compounding—threats from China, Russia, North Korea, Iran, non-state actors, homegrown terrorists, extreme weather, and more.

While my primary interest in snow revolves around things like skiing and streamflows, I’m casting a broad net here at snow.news, and I know I can’t tell the story of snow without exploring the morbid and tragic angles.

As we’ve seen in Ukraine, winter weather remains a part of current warfare. Although snow wasn’t an issue when the United States fought in Vietnam and Iraq, our nation’s longest war in Afghanistan featured a “fighting season” largely dictated by snow cover.

Looking ahead, the rapidly changing cryosphere is a key military issue in the 21st century. “Arctic Heating Up Literally and as Scene of Strategic Competition” is how the U.S. Department of Defense titled an April 2023 piece.

Or see this August 2025 story in The Wall Street Journal, titled “Very Cold War,” about preparations for a “subzero battlefield” in the increasingly contested Arctic.

Below are the first 6 of 13 examples from military history in which snow, ice, and winter weather were defining features.

This mile-wide and inch-deep approach scratches the surface. If you’d like to learn more about these episodes, I’ve listed resources for further reading; some of the books are still on my docket, but anything marked with a ✅ means I’ve read the source and recommend it.

I’ve been toying with the idea of writing a book about snow someday, and if I ever take the plunge, a major chapter will focus on winter warfare. In this series, I’m reconnoitering the terrain. Don’t hold your breath for the book: I may need to wait until my retirement, given that my first book—Endangered: Biodiversity on the Brink—entailed slaving away for years in exchange for a pittance.

1) Battle of Trenton and Valley Forge winter in the Revolutionary War

On the night of December 25/26, 1776, General George Washington led his troops across the icy Delaware River in a daring winter maneuver and ensuing battle during the fledgling nation’s fight for independence. Months after the Declaration of Independence, the fate of the colonies was precarious, and the future of the young republic was in doubt.

We’re preparing to celebrate the nation’s Semiquincentennial (250th anniversary) of the 1776 American Revolution, so it’s easy to associate that year with celebration and triumph. Yet from a military perspective, 1776 was filled with crushing defeats for the Continental Army, most notably the British rout in the Battle of Long Island, which led to the loss of New York City and a grueling retreat across New Jersey.

As 1776 drew to a close, morale among the revolutionary troops was dismal. Supplies were scarce, enlistments were expiring, and many wondered if the Continental Army could survive the winter. But Washington decided to gamble and led the famous charge across the Delaware, surprising the Hessian troops at Trenton, New Jersey. The Hessians—German soldiers hired by the British—didn’t expect their foes to strike during such inclement conditions.

The weather at the time was a classic nor’easter storm that pelted the soldiers with snow and sleet. Incredibly, some of the troops made the crossing without any boots and wrapped rags around their feet to prevent frostbite, or at least tried to.

Washington’s victory in the Battle of Trenton helped turn the war around. Soon thereafter, Washington succeeded again in the Battle of Princeton, further boosting the esprit de corps and helping improve enlistments in the army.

There was still a lot of fighting ahead. After the British captured Philadelphia in the fall of 1777, Washington’s army set up a winter camp in Valley Forge, about 20 miles northwest of the city, where they faced frigid conditions marked by deprivation and disease. Some 2,000 of the 12,000 troops perished before spring. But the Continental Army somehow endured that brutal winter and, with support from the French, would slowly gain control of the war, which ended with the Treaty of Paris in 1783.

📖 Learn more:

✅ Washington's Crossing, David Hackett Fischer, 2004.

2) Napoleon’s Russian Campaign of 1812

Things didn’t go so hot for Napoleon when he tried to invade Russia in 1812. France’s supreme military commander set out to punish Russia because Tsar Alexander I wasn’t participating in an economic blockade against Britain, France’s main rival. Napoleon envisioned a quick victory to bring the Russians back into the fold and secure France’s dominance in Europe, but that proved to be a fool’s errand.

In June 1812, Napoleon led his Grande Armée, comprising more than 600,000 soldiers, into Russia. Rather than directly confronting the invaders, the Russians steadily retreated while burning crops, villages, and supplies in their wake in a scorched-earth campaign on their own turf. The Russian strategy strained Napoleon’s supply lines, but the French eventually reached Moscow—only to find that much of the city had already been burned to the ground.

Napoleon hoped to negotiate a peace with the Tsar, but with no agreement in sight, the Grande Armée began a tardy retreat in October, exposing it to increasingly dire weather conditions. Soon, the ill-prepared soldiers were facing frostbite and hypothermia as their horses were freezing to death. Starvation stalked the retreating army, with some units reportedly turning to cannibalism to survive.

Historians would eventually highlight the role of “General Winter” or “General Frost” in precipitating the disaster, but it turns out that most of the casualties occurred long before the onset of cold weather due to factors such as disease and hunger. You can see that in the famous graphic below by Charles Joseph Minard, a French civil engineer who charted the army’s size during the advance (beige) and the retreat (black) while also plotting the temperatures they faced on the way home.

Data visualization guru Edward Tufte, whose undergraduate political science class more than 30 years ago sparked my interest in data analysis, called this flow map “probably the best statistical graphic ever drawn.”

It wasn’t only the weather that doomed Napoleon’s troops. But by staying too long in Moscow, Napoleon left his soldiers vulnerable to the Russian winter, offering a lesson that Adolf Hitler would ignore more than a century later.

📖 Learn more:

Moscow 1812: Napoleon’s Fatal March, Adam Zamoyski, 2005.

3)The 1854 Battle of Balaclava

I view the balaclava as must-have gear for skiing and snowboarding in cold weather. I just wish the name of the garment didn’t constantly remind me of baklava, that scrumptious Greek dessert with honey and phyllo dough!

The name of the accessory is rooted in a famous fight during the Crimean War (1853-1856) that became known as the Battle of Balaclava. During this episode of European warfare, Britain, France, and the Ottoman Empire were fighting against Russia. The battle on the Black Sea coast of Crimea was the site of a disastrous cavalry charge by the British straight into the Russians’ artillery fire that was immortalized in Alfred, Lord Tennyson’s poem, “The Charge of the Light Brigade.”

Although the battle took place in October, the weather was cold enough that soldiers’ families and supporters back home knitted special garments to keep the warriors’ heads warm.

In his Online Etymology Dictionary, Douglas Harper writes that the clothing was initially called a Balaclava helmet. The term doesn’t appear before 1881 and “seems to have come into widespread use in the Boer War,” when British troops once again faced bitter cold, according to Harper.

📖 Learn more:

24 Hours at Balaclava, Robert Kershaw, 2019.

4) The White War in the Italian Alps: 1915–1918

World War I conjures images of trench warfare in the muddy lowlands of Europe, but part of the conflict was waged high in the mountains as Italy and Austria-Hungary fought for control of the Alps and Dolomites.

In an extreme alpine environment, the soldiers faced blizzards, brutal temperatures, and dozens of feet of snow in what became known as “The White War.” Some of the fighting transpired at elevations above 10,000 feet. Historians have noted that roughly two-thirds of the dead fell prey to the elements, such as avalanches, frostbite, and exposure, and only one-third perished due to the fighting itself.

Like much of the rest of World War I, the Italian campaign was marked by outrageous death tolls and casualties that were incurred in exchange for tiny territorial gains. Not only were trenches cut into the mountains, but soldiers were also ensconced in ice caves. Tunnels were bored into glaciers.

Avalanches took an almost inconceivable toll on the armies, with some estimates of the fatalities in the tens of thousands. In one notable incident, known as the “White Friday” disaster, avalanches possibly triggered by artillery fire may have killed 2,000 people in a single day.

📖 Learn more:

The White War: Life and Death on the Italian Front, 1915–1919, Mark Thompson, 2009.

✅ “The Most Treacherous Battle of World War I Took Place in the Italian Mountains,” Brian Mockenhaupt, Smithsonian Magazine, June 2016.

✅ “A Century Later, Relics Emerge From a War Frozen in Time,” Michele Gravino, National Geographic, October 18, 2014.

5) The Winter War: Soviet invasion of Finland in 1939

At the start of World War II, the Soviets were nervous about their northwestern border. In response, Moscow pressured Finland to cede territory so it could secure a naval base and push the frontier back from the vulnerable city of Leningrad. The Finns’ resistance prompted nearly half a million of Joseph Stalin’s troops to invade on November 30, 1939, beginning what became known as “The Winter War.”

Outnumbered, the Finnish troops were able to check the Soviet advances due to their better preparations for winter warfare, including proper camouflage and their reliance on the “Motti” strategy, in which ski troops would divide and conquer Soviet columns in snowy forests.

In the end, the Soviets prevailed over Finland, which ceded around one-tenth of its territory, but the nation retained its independence. Although the war was a defeat for Finland, Soviet casualties were far higher, and the weaknesses in the Red Army were exposed, helping inspire Hitler to eventually break his alliance with Moscow and attack the Soviet Union.

📖 Learn more:

White Death: Russia's War on Finland 1939–40, Robert Edwards, 2006.

6) Nazis and nukes: Norwegian heavy-water sabotage

What if Hitler got the bomb? A terrifying thought, and it could have happened. Were it not for a daring operation in the snowy mountains of Norway, the world might have eventually faced a nuclear-armed Third Reich, though historians still debate how close the Germans came to this nightmare scenario.

During World War II, German scientists were trying to build an atomic bomb, just like their counterparts in the Manhattan Project in the United States. The German strategy hinged on developing a supply of “heavy water,” a form of H2O in which the hydrogen atoms are the isotope deuterium. This heavy water could be used in a nuclear reactor to sustain a chain reaction that converts natural uranium into plutonium-239. The Germans had uranium, but they lacked the means to enrich it, so heavy water offered a way to create fissile plutonium that could be used in weapons.

The Germans were busy producing heavy water at Vemork, a hydroelectric plant located in a gorge in the Telemark region of Norway, so the facility became a prime target. First, a 1942 British glider assault ended in disaster. Then, in a 1943 commando raid that would later be immortalized in books and movies, Norwegian resistance fighters used skis to reach the plant in harsh winter conditions and blow up the heavy-water cells.

The Germans tried to restart operations and ship the remaining heavy water to the motherland, but once again, saboteurs struck and sank the ferry that was transporting the valuable cargo, killing some Norwegian civilians in the process.

📖 Learn more:

✅ The Winter Fortress: The Epic Mission to Sabotage Hitler's Atomic Bomb, Neal Bascomb, 2017.

Assault in Norway: Sabotaging the Nazi Nuclear Program, Thomas Gallagher, 2010.

Stay tuned for Part 2 . . .

In the second half of this series, I cover other conflicts in which snow and winter weather figured prominently. I also write about the Arctic's growing strategic importance as the cryosphere is transformed by climate change.

And, sadly, I look ahead to the not-so-distant future, when geopolitical instability could spiral out of control and lead to a nuclear winter that threatens billions of lives and plunges the planet into a cold, dark era that resembles a mini ice age . . .

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I’m stoked to be entering my third season here at snow.news! I’m now making a concerted push to expand its readership. And I need your help.

I don’t charge money for this 100% free newsletter, but I do aim to reach the four-figure mark in subscribers, which will earn me more visibility on Substack and help this journalistic enterprise grow organically.

To cut to the chase: I currently have 689 subscribers and I want to break the 1,000 milestone this season.

I know I can’t achieve this goal without the help of my current readers, so in this post I’m respectfully asking for your assistance in promoting snow.news while also providing opportunities for you to shape the project going forward.

How you can help

I’m an introvert, so self-promotion doesn’t come naturally to me. But if you enjoy reading snow.news and would like to help expand its reach, please consider taking one or more of the steps below:

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snow.news so far . . .

My introductory post went live on October 17, 2023. It graced the inboxes of 14 people, many of them sharing DNA with me.

I’ve since published 52 other posts that have focused on the state of the West’s snowpack and the latest in snow science research. I’m practicing what I call “snow journalism,” a fact-based reporting enterprise dedicated to covering all things snow. I’ve also mixed in some personal narratives and my own photography while keeping it fun with content related to snow culture and skiing/snowboarding.

snow.news has a few regular features:

• Snowpack and snow drought updates: The latest data and visualizations tracking the health of the West’s snowpack during the current season.

• snow.news roundup: A periodic collection of briefs on the latest snow-related news, research, and oddities, with links to relevant coverage and content online.

• SnowSlang: An A-to-Z look at snow-related terminology. My most recent post was L is for “lake effect snow,” and you can access a roundup of some prior content through this post or my snowslang.com website.

• SnowVis: Data visualizations that explain snow-related topics, including a variety of charts, maps, diagrams, and animations that tell the story visually.

• Water Desk stories: I partly use this newsletter as an outlet for my snow-related work at The Water Desk, an independent journalism initiative at the University of Colorado Boulder that I co-direct.

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Marketing strategies I’ve pursued

To grow the subscriber base, I first reached out to family, friends, colleagues, and anyone else I could think of who might be interested. That got me my first couple of hundred subscribers—an affirming boost out of the starting gate.

I then started to do limited advertising on Facebook and Instagram to promote the newsletter. It’s been a fascinating look under the hood of social media and the potential/perils of digital marketing.

After conducting numerous experiments, dealing with a ton of spam comments, and spending around $1,000, I acquired nearly 400 new subscribers. Yes, I’m paying out of my own pocket to attract people to a free newsletter—this passion project is that important to me!

I’ll continue experimenting with ads, but I’m also heartened that I’m increasingly gaining subscribers who arrive organically via the Substack app, social media shares, search engines, even artificial intelligence chatbots.

I now believe that the more high-quality content I produce, the more readers and subscribers I’ll attract. That’s encouraging for a journalist who has struggled to find an audience ever since leaving the daily newspaper business nearly 20 years ago.

I’m incredibly grateful that so many people have decided to sign up and remain loyal readers—it’s extremely rewarding even though I’m offering something for free.

Last but not least on the marketing front, I adopted a three-mile stretch of U.S. 550 around Silverton, Colorado. I get to advertise snow.news on two road signs in exchange for “sprucing up” the roadside on one of the most beautiful stretches of highway in the state. It’s hard to say how many subscribers I’ve gained from this strategy, but I’m (strangely) excited to do the volunteer work for both altruistic and anthropological reasons.

Thanks so much for reading snow.news and for your continued support!

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California’s glaciers are disappearing

A new study offers a grim prognosis for the remaining glaciers in California’s Sierra Nevada.

Previous research suggested that the mountain range’s glaciers might have disappeared thousands of years ago, during warm spells since the end of the last ice age. But this new paper argues that a glacier-free Sierra Nevada is unprecedented in the Holocene, the current geological epoch that began about 11,700 years ago.

“Our reconstructed glacial history indicates that a future glacier-free Sierra Nevada is unprecedented in human history since known peopling of the Americas ~20,000 years ago,” the scientists write in Science Advances.

Due to human-caused climate change, summer temperatures in California have already warmed by 2° Celsius (3.6° Fahrenheit) in the past century. The graphic below from the paper shows the projected trajectory of four glaciers in the Sierra Nevada.

Ian James at the Los Angeles Times has an informative story about the new study.

“It means that when these glaciers die off, we will be the first humans to see ice-free peaks in Yosemite,” lead author Andrew Jones, a researcher at the University of Wisconsin, Madison, told James. “Glaciers are touchstones between the past and the present, and it’s just so visceral when you can see how it used to be and how it is today.”

James also notes that “when the snowpack is gone by late summer, the glaciers that remain, often in the shadows of peaks, release meltwater that keeps streams flowing at the driest times of year.”

If you’re hungry for more depressing news about glaciers, see this in-depth story by NPR’s Rob Schmitz about the melting in Europe and the consequences for rivers on the continent, which is warming at double the global rate.

Climbing and skiing Mount Everest—without bottled oxygen

Imagine setting off on a ski run that begins near the cruising altitude for commercial airliners. Sounds insane, but Polish athlete Andrzej Bargiel has a habit of making such death-defying descents in the Himalayas. His latest exploit: scaling 29,032-foot Mount Everest, clipping into skis, and making turns down the world’s tallest peak—all without supplementary oxygen.

Check out the video below for some footage of the unprecedented feat:

Bargiel spent nearly 16 hours climbing above 8,000 meters (26,247 feet) in what’s known as Everest’s “death zone” due to the paucity of oxygen. His descent required passage through the perilous Khumbu Icefall, where he was guided by a drone flown by his brother.

“More than 6,000 people have climbed Everest, but fewer than 200 have ever done it without supplementary oxygen,” according to Red Bull, the energy drink company that sponsors Bargiel. In 2018, Bargiel made the first skiing descent of K2, the planet’s second-highest mountain—something that still hasn’t been replicated.

If you want to see some stunning photos of the expedition, check out this page from Red Bull (the images are copyrighted, so I’m not including them here). There’s more imagery on Bargiel’s Instagram page:

Rising temperatures are driving drought in the West

In my previous post, I discussed how human emissions are contributing to the megadrought in the American Southwest. It’s a one-two punch. Greenhouse gases and aerosol emissions have been altering storm tracks and reducing precipitation. At the same time, warmer temperatures are aridifying the region, drying out soils, shrinking the snowpack, and making the atmosphere thirstier.

The instructive graphic below from climate.gov quantifies the impact of these two forces. From 1948 to 1999, low precipitation was to blame for the West’s drought (purple shading), but in the 2000-2022 period, greater evaporative demand driven by hotter temperatures has come to dominate in many areas (orange shading).

“The Great Plains and the inter-mountain basins and valleys have flipped from a drought regime driven mostly by precipitation to one driven strongly by drying heat,” according to Rebecca Lindsey at climate.gov. “A shift toward heat-dominated droughts means that even in years when precipitation is normal, the threat of drought remains, and it will only get worse with continued human-caused global warming.”

The data in these maps stems from a NOAA-funded 2024 study in Science Advances, titled “Anthropogenic warming has ushered in an era of temperature-dominated droughts in the western United States.” Under a high-emissions scenario, “droughts like the 2020–2022 event will transition from a one-in-more-than-a-thousand-year event in the pre-2022 period to a 1-in-60-year event by the mid-21st century and to a 1-in-6-year event by the late-21st century,” according to the study.

I came across this graphic thanks to a helpful article from David Condos at KUER. Condos interviewed Dan McEvoy, a climatologist with the Western Regional Climate Center, who was the subject of a Q&A on snow droughts that I published in June.

“If you have the same amount of water in the winter in 2025 compared to 1950, that’s not going to translate to the same amount of water into the system that you had in 1950,” McEvoy told Condos.

This phenomenon isn’t limited to the American West. Condos notes that “a recent University of Oxford study suggests that the thirsty atmosphere has increased global drought severity by 40% since the early 1900s.”

The skyrocketing cost of lift tickets at ski resorts

Skiing and snowboarding can be super expensive, especially if you don’t have a season pass and wait until the last minute to buy lift tickets. Years ago, it was news when the walk-up rate at some resorts crossed the $200 threshold; now, some ski areas are charging ticket-window rates of around $300 per day during peak periods.

Stuart Winchester, who covers ski resorts at The Storm Skiing Journal and Podcast, has been tracking the numbers and recently posted the chart below showing the meteoric rise in peak lift ticket prices since 2000, using a database of 37 resorts.

The average price skyrocketed 387%, from $53 in the 2000-2021 winter to $258 in the 2024-2025 season, but much of the rise is actually due to inflation. Using the Consumer Price Index, I calculated the 2000-2001 average price to be $100 in 2025 dollars, so the increase in real terms is 158%, which is still mighty steep.

Over the past quarter-century, resort companies have shifted to selling season passes (e.g., Epic and Ikon) that cover multiple ski areas. The outrageous rates for single-day tickets have motivated many skiers and snowboarders to buy the passes, which can now top $1,000 per season. If you slide on snow frequently, these passes can be a good deal, but when you add in the costs for travel, lodging, equipment, and food/beverages, it’s hard to avoid shelling out big bucks to hit the slopes.

Skiing and snowboarding are pricey, but as I like to say, they’re cheaper than therapy and potentially just as effective.

Bye-bye, basin snowpack maps?

During the snowpack season, I have regularly consulted this site run by the Natural Resources Conservation Service to download and share maps showing how snow is stacking up in river basins across the West.

Alas, the federal government has decided to retire these maps, and during the ongoing shutdown, it has added this cheeky proclamation:

Snowpack data are also usually available on the NRCS iMap interactive, which includes readings from individual SNOTEL stations and streamflow information. Unfortunately, only some of the basins are now reporting snow water equivalent.

The map below, which shows total precipitation in each watershed, indicates that the West’s water year has started wet, but in many places this moisture has fallen as rain rather than snow. Some of these percentages are enormous because the historical median is very low at the beginning of the season.

Here in southwest Colorado, the past week has been incredibly wet, thanks to remnants of two tropical systems from the Pacific. My weather station has recorded more than six inches of rain since October 9, but the actual total is even higher—it was so stormy that my rain gauge went offline for a while! The tropical origin of the storms means they’ve come in warm, so only the highest peaks around here have received snow.

The map below shows total snowfall in the West from October 1 to 13.

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I’m excited to share the story below that I recently wrote for The Water Desk, a program at the University of Colorado Boulder’s Center for Environmental Journalism that I co-direct.

In case you missed it, I sent out another post last week, but unfortunately, only 41% of subscribers received it. D’oh! I shared some of my favorite data visualizations, and I think the huge animated GIFs and copious images may have upset the email gods, so the message got filtered out. In the future, I’ll try to keep my visuals in check to appease the inbox overlords.

The American Southwest has been gripped by an epic drought that has lasted decades and strained the fast-growing region’s naturally limited water resources.

The megadrought—thought to be the worst in at least 1,200 years—has caused reservoir levels to plummet on the Colorado River and shriveled the Rio Grande. The dry times have also stressed imperiled ecosystems, heightened wildfire risks and curtailed outdoor recreation.

While the drought’s consequences are easy to see, its causes and prognosis are trickier to disentangle, requiring scientists to look deeply into precipitation deficits, rising temperatures and changing patterns in the atmosphere and ocean.

Long before humans began altering the climate with greenhouse gases and other air pollutants, the Southwest was subject to feast-or-famine weather featuring extreme dry spells, raising the possibility that this current drought is just part of that natural variability.

What scientists are exploring now is how the human touch is imprinted on the drought due to our ongoing transformation of the climate, atmosphere and oceans.

Three recent scientific studies identify human emissions as a key driver in the precipitation declines that have helped cause the Southwest’s current drought, which has been made much worse by rising temperatures due to climate change.

The papers, published in the July 9 issue of Nature Geoscience and the August 13 issue of Nature, focus on what’s been happening in and above the Pacific Ocean to help explain recent precipitation deficits in the Southwest. As carbon emissions continue to rise, all three papers conclude that human-caused warming is likely to make drought a more persistent feature in the decades ahead.

The three recent studies examine why changes in and above the ocean have shifted storm tracks and made the Southwest’s weather drier, but that’s not the whole story about the drought. The picture is even bleaker when we account for what’s happening to the region’s warming landscape and an increasingly thirsty atmosphere.

Another line of research has found that higher temperatures alone are causing the Southwest to “aridify” by drying out soils, boosting evaporation rates and shrinking the snowpack. Known as a “hot drought,” this aridification due to warming would be troubling enough for the Southwest’s water resources and society. But the three recent studies, which focus on precipitation shortfalls, add another level of worry: relief falling from the skies as raindrops and snowflakes appears increasingly unlikely.

Study 1: Why the Pacific’s rhythm is stuck

One of the studies, “Human emissions drive recent trends in North Pacific climate variations,” focuses on the Pacific Decadal Oscillation (PDO) and why it has been stuck, rather than oscillating over recent decades as its name would suggest.

The PDO is a natural rhythm in sea-surface temperatures in the North Pacific Ocean that has warm and cool phases. The cycle, which is similar to the El Niño/La Niña pattern in the tropical Pacific, was thought to last about 20 to 30 years, but in recent decades it has predominantly been in the cool or “negative” phase, which tends to make the Southwest drier.

“The PDO has been locked in a consistent downward trend for more than three decades, remanding nearby regions to a steady set of climate impacts,” according to the study. “The ongoing, stubbornly persistent, cold phase of the PDO is associated with striking long-term trends in climate, including the rate of global warming and drought in the western United States.”

The conventional scientific understanding of the PDO holds that the pattern waxes and wanes largely due to natural “internal” variability. But this recent study, which relies on 572 climate simulations processed on supercomputers, argues that the PDO is, in fact, very much influenced by human activities and our air pollution. These external forces account for 53% of the variation in the PDO.

“Overall, we find that human activity is a key contributor to multi-decadal trends in the PDO since the 1950s,” according to the paper.

It wasn’t always this way. Between 1870 and 1950, the PDO’s changes were internally generated, with external forces explaining less than 1% of the variability.

“It seems like as long as emissions continue, we’re going to be stuck in this current phase of drought,” said lead author Jeremy Klavans, a postdoctoral associate in the Department of Atmospheric and Oceanic Sciences at the University of Colorado Boulder. “If emissions were to abate, we think that the PDO would be able to vary freely again, and drought would be, again, a thing of chance. There would be the chance to end the drought.”

The researchers say they used an “extraordinarily large ensemble” of climate simulations to isolate the signal of human-caused climate change from the noise of natural variability.

“It takes a really large ensemble to find this signal, and that’s because we think that the signal-to-noise ratio in climate models is too low,” Klavans said.

That’s distressing news for the region’s water managers, who are already grappling with limited supplies. “We expect there to be reduced water supply in the form of precipitation, including snowfall, in the next 20, 30 years, so as they’re making planning decisions for how to allocate water resources or what infrastructure to build, they should expect less precipitation,” Klavans said.

“It certainly seems that in the near term, given the choices that we’ve made, the PDO will continue to be stuck in drought,” Klavans said.

Study 2: Deep drought long ago offers insights for today

This isn’t the first time the Southwest has faced a megadrought.

Another study, “North Pacific ocean–atmosphere responses to Holocene and future warming drive Southwest US drought,” looks back about 6,000 years ago to a time known as the mid-Holocene. Back then, the Southwest suffered a monster drought lasting thousands of years, but this occurred many millennia before humans began changing the climate with our emissions of greenhouse gases and other pollutants.

During the mid-Holocene, there was a different external force at play: an increase in the amount of solar radiation hitting the Northern Hemisphere during the summer, which also altered vegetation patterns on the land.

In a process known as the Milankovitch Cycles, the Earth’s orbit and movement change regularly over the span of tens of thousands to hundreds of thousands of years. Like a spinning top, the planet wobbles. The tilt of its axis also oscillates back and forth. And Earth’s orbit around the sun alters from a near-perfect circle to a slightly more elliptical path.

The Milankovitch Cycles caused more sunlight to hit the Northern Hemisphere in summer during the mid-Holocene warming. One of the effects was a more vigorous West African monsoon and the greening up of the Sahel and Sahara deserts, which caused those areas to absorb more heat as the land surface darkened. Similar processes happened elsewhere. The paper concludes that this external forcing had a major impact on the Pacific Ocean and the PDO, similar to how human-caused warming is playing out today and into the future.

“People used to think that droughts in the Southwest were just occurring kind of like as a random roll of the dice, and now we can see that actually it’s like a pair of loaded dice,” said lead author Victoria Todd, a Ph.D. candidate at the University of Texas studying paleoclimatology. “This drought is occurring in wintertime, which is really important for snowpack in the Rockies and its role in Colorado River flow and Western U.S. water resources in general.”

The authors write that “our results suggest that these precipitation deficits will be maintained by a shift to a more permanent negative PDO-like state as long as hemispheric warming persists.”

“Such sustained drying and intense reductions in winter precipitation would have catastrophic impacts across the Southwest United States, particularly in the Colorado River Basin,” according to the paper.

Todd and co-authors investigated what happened during the mid-Holocene by using an analysis of leaf waxes extracted from the cores of lake sediments in the Rocky Mountains. Plants create waxy coatings on their leaves to minimize water loss and protect themselves. These hardy waxes can persist for ages when they’re deposited into sediments, allowing them to reveal critical clues about what the Earth was like when the plant was alive. By analyzing the leaf wax’s isotopes—special forms of chemical elements—researchers can paint a picture of precipitation patterns long ago.

The findings about the mid-Holocene and their analysis of modern climate projections led the researchers to conclude that current models underestimate the size of the precipitation deficits caused by warming. Both in the past and the present, the warming impacts the PDO and steers storms away from the Southwest.

If the Southwest’s drought were just due to natural variability—a fair roll of the dice—we’d expect the PDO to get unstuck eventually and for the dry spell to break. But the research concludes that pure chance is no longer governing the system. Humans are tilting the odds.

“If global temperatures keep rising, our models suggest the Southwest could remain in a drought-dominated regime through at least 2100,” co-author Timothy Shanahan, associate professor at the University of Texas’ Jackson School of Geosciences, said in a press release.

“Many people still expect the Colorado River to bounce back,” Shanahan said. “But our findings suggest it may not. Water managers need to start planning for the possibility that this drought isn’t just a rough patch—it could be the new reality.”

Study 3: The effects of aerosols and tropical ocean warming

The third paper, “Recent southwestern US drought exacerbated by anthropogenic aerosols and tropical ocean warming,” offers a hint of optimism but also warns about long-term drought in the Southwest.

The study identifies two human-caused drivers for the shortfall in winter-spring precipitation in the region: the effects of aerosol pollution in the atmosphere and global warming’s impact on ocean temperatures in the tropical Pacific. These forces have weakened the Aleutian Low, the semi-permanent low-pressure system in the North Pacific that directs storms toward the Southwest when it’s stronger.

The study concluded that the post-1980 period in the Southwest has seen record-fast drying of soil moisture due to the precipitation declines and human-caused warming. Natural variability still plays a significant role in the Southwest’s precipitation, according to the researchers, but humanity is making its mark.

“We are not saying 100% it’s because of climate change or because of human emissions, but there’s a role from human emissions,” said lead author Yan-Ning Kuo, a Ph.D. candidate in atmospheric science at Cornell.

Aerosols may conjure deodorant sprays, but in this context, they refer to a broad class of airborne particles that are emitted by human activities, such as burning fossil fuels, and natural causes, such as dust from deserts or sea salt from the ocean.

Some aerosols, such as the sulfates emitted when coal and oil are burned, reflect incoming sunlight and can have a cooling effect. Others, such as sooty black carbon, absorb solar radiation and have a warming effect. Aerosols can also affect cloud formation.

In this study, the authors argue that aerosols can have a significant effect on the atmosphere as they drift eastward from Asia, where booming economies and lax regulations in some areas have caused air pollution to soar in recent decades.

“We actually feel like there’s a hope for good news on the precipitation side because as we clean up aerosols, precipitation might rebound a little bit,” said co-author Flavio Lehner, assistant professor in Cornell’s Earth and Atmospheric Sciences Department.

But while reduced aerosol pollution might help the Southwest’s drought, the emissions of greenhouse gases, such as carbon dioxide, keep rising, and warming temperatures continue to aridify the Southwest’s landscape.

“​​From a precipitation perspective, we might see a recovery in the next decade or two, but together with the continued warming, that might not help much with the drought,” Lehner said. “In none of these scenarios, I think everybody would agree, does it look like the Southwest is not going to be in trouble.”

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