Climate Change Is Pushing the US off a ‘Snow-Loss Cliff’

It's not your imagination: There really is a lot less snow than there used to be.

A big study published on Wednesday in the journal Nature shows that seasonal snowpack has shrunk substantially across regions in the northern hemisphere between 1981 and 2020, with some of the greatest declines — between 10% and 20% per decade — seen in parts of the U.S.

In some places, the lack of snow will seriously affect freshwater availability, while in other, less thirsty areas its primary impact will be on skiing and other winter recreation.

"The train has left the station for regions such as the Southwestern and Northeastern United States," said Alexander Gottlieb, a PhD student at Dartmouth University and the study's lead author, according to a press release.

"By the end of the 21st century, we expect these places to be close to snow-free by the end of March. We're on that path and not particularly well adapted when it comes to water scarcity."

The new evidence comes after a rough 2023 for the world's ice, as study after study forecast troubling times ahead for the planet's ice sheets, glaciers and sea ice.

No More Snow?

To come to their grim conclusion on snow, the researchers used AI to analyze snowpack trends in 169 major river basins across the northern hemisphere, and found a "robust" declining trend in 82 of them, with many showing clear signs of climate change driving snow loss.

They also found that most areas likely won't see a smooth, predictable decline in snowpack. Instead, an area experiencing a slow decline in its snow could rapidly fall off what the authors call a "snow-loss cliff" beyond certain temperature thresholds.

"Snow observations are tricky at the regional scales most relevant for assessing water security," said Justin Mankin, an associate professor at Dartmouth and the study's senior author.

"Snow is very sensitive to within-winter variations in temperature and precipitation, and the risks from snow loss are not the same in New England as in the Southwest, or for a village in the Alps as in high-mountain Asia," he said.

Somewhat counterintuitively, the study also found some areas with increases in snowpack, as climate change ups the amount of moisture in the atmosphere and allows more snow to fall. They include parts of Alaska, Canada and central Asia.

Still, many places that rely on the snowpack for water are seeing sharp declines. These include the American Southwest, as well as parts of central and eastern Europe. In other places like Vermont and New Hampshire, water is more readily available, but the harm to the winter tourism industry — including to other outdoor sports like pond hockey — are already becoming clear.

And after a wet winter last year, the American West is now seeing a decline in snow. As of January 10, California's mountains had as little as 29% of the average amount of snow for this date, according to data from the state's Department of Water Resources.

"Water managers who rely on snowmelt can't wait for all the observations to agree on snow loss before they prepare for permanent changes to water supplies. By then, it's too late," Mankin said.

"Once a basin has fallen off that cliff, it's no longer about managing a short-term emergency until the next big snow. Instead, they will be adapting to permanent changes to water availability."