Warming temperatures are shrinking snowpack in key Canadian watersheds, study suggests

A record-breaking snow drought in the western U.S. is raising concerns about water scarcity and wildfires next summer. A new Canadian study suggests the conditions could signal a longer-term trend that threatens water supplies for millions across the country.

Snow cover in the western U.S. is well below what it normally is at this time of year, and the lowest ever recorded since NASA’s Terra satellite began monitoring in 2001. 

A warming climate is likely making this more common. The snow deposited in winter on parts of western Canada, and the water contained in that snow, declined from 2000 to 2019, according to the study from researchers at Concordia University in Montreal. 

The areas that saw significant declines made up only three per cent of the country, but affected the headwaters of major rivers in the Canadian Rockies. The study also found smaller declines in other parts of southern Canada, which were not statistically significant on their own.

"But we are still seeing some sort of decline. So when we put them together, we realize that within the 25 major drainage basins that we have in Canada, 14 of them are getting affected," said Ali Nazemi, co-author of the study and associate professor of engineering at Concordia.

The declines in snow have major consequences for everything from municipal water systems to agriculture, lake water levels and shipping, and wildfire risk in Canada’s forests.

“I often refer to the snowpack, especially in mountain areas, as this natural water tower,” said Kate Hale, assistant professor at the University of British Columbia.

Like human-made water towers, the snowpack stores the water and then releases it when it's needed the most, she said, and those mountains naturally release the water in the summer when it's most needed by humans for growing food and other uses.

The low snow is wreaking havoc on the ski season at major resorts in the region. Slopes across B.C. have had to pause operations or scale back because of the lack of snow and warm weather. Vail Resorts, which owns ski slopes across Canada and the U.S., is reporting one of the worst early season snowfalls at its western U.S. resorts. Its resort in Whistler, B.C. also had a slow start to the season, but improved with snowstorms by the end of December 2025.

Meanwhile, Vancouver is facing its first winter without snow in 43 years.

A snow drought is often caused by a lack of precipitation. But this year, precipitation has been closer to normal — it has just fallen as rain rather than snow, says Alejandro Flores, a professor of geosciences at Boise State University in Idaho, leading to what he calls a “wet snow drought.”

“This is certainly something that is consistent with what we expect in a warming world. We expect a preferential transition away from snow and toward rain."

Warmer fall temperatures can carry into winter, causing precipitation that would normally fall as snow in December or later to come down as rain. That rain not only fails to build the snowpack, but can also wash away what little snow cover is already on the ground, he said.

Snow cover in the mountains acts as a store of water, holding it until spring and releasing it as the snow melts in warmer months. That meltwater feeds water systems millions of people rely on, as well as forests and other ecosystems.