Study shows rising temperatures are causing snowfall in Canada’s major watersheds

Record-breaking snowfall in the western US is raising concerns about water shortages and wildfires next summer. A new Canadian study suggests the conditions may indicate a long-term trend that could jeopardize the water supply for millions of people across the country.

Snow cover in the western US is well below normal for this time of year, and lowest ever recorded Since NASA’s Terra satellite began monitoring in 2001.

A warming climate is probably making it more common. In parts of western Canada, winter snow accumulation and the water contained in that snow have declined from 2000 to 2019, According to the study From researchers at Concordia University in Montreal.

The areas that saw significant declines were only three percent of the country, but the headwaters of major rivers in the Canadian Rockies were affected. The study also found smaller declines in other parts of southern Canada, which in themselves were not statistically significant.

“But we’re still seeing some type of decline. So when we put them together, we find that 14 out of the 25 major drainage basins that we have in Canada are being affected,” said Ali Nazemi, co-author of the study and associate professor of engineering at Concordia.

Declining ice has major impacts on everything from municipal water systems to agriculture, lake water levels and shipping, and the threat of wildfire in Canada’s forests.

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

Like man-made water towers, the snowpack stores water and then releases it when it’s needed most, he said, and these mountains naturally release water in the summer when humans need it most for growing food and other uses.

What’s up with the snow this year?

Low snowfall is wreaking havoc on the ski season at the region’s major resorts. slopes across bc Had to stop operations or reduce work Due to lack of snow and hot weather. Vail Resorts, which owns ski slopes across Canada and the US Report of one of the worst snowfalls of the season At his western American resorts. Its resort in Whistler, BC, also had a slow start to the season, but improved with snow storms by the end of December 2025.

Meanwhile, Vancouver is coping with first winter without snow In 43 years.

Snow drought is often caused by a lack of rainfall. But this year, precipitation has been closer to normal — it has fallen as rain rather than snow, says Alejandro Flores, a geology professor at Boise State University in Idaho, causing 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.”

Warm temperatures can drop in winter, causing precipitation that usually falls as snow in December or as rain later. He said the rain not only fails to form snow cover, but can also wash away what little snow is already present on the ground.

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

“So the concern is that some of our forests will become depleted of water early this year and that will potentially increase the risk of wildfires across North America,” Flores said.

Will these trends continue?

Nazemi says this year’s conditions show that the trend of low snow affecting the Canadian Rockies extends south through the mountains in the western US. His team has come up with a new measure to calculate how much water is actually in the snowpack, which they call “snow water availability.”

They used remote sensing techniques from satellites to get more precise measurements of ice water, examining data from 2000 to 2019, covering Canada and Alaska.

The watersheds most affected by declining snowmelt were the Okanagan in BC, the Assiniboine-Red River Basin in Manitoba, and the Saskatchewan River Basin. The decline could also reduce flows in the Fraser River and St. Lawrence River, on which millions of people depend for water and hydropower.

Nazemi said declining ice cover has affected water security in the past. In 2015, his team’s data showed that there was a large decline in winter snowfall in the Rocky Mountains. By summer, mid-B.C. was inside severe droughtWater restrictions and a ban on fishing were imposed on the Okanagan River to protect fish stocks.

Nazemi pointed to another example in 2012, when weather patterns led to less snowfall in Eastern Canada. that year, Great Lakes water levels fellThat’s causing problems for cargo ships trying to sail across the lakes to the major ports of Montreal and Toronto.

“We should expect some vulnerabilities that are going to intensify in the future,” Nazemi said.

But how quickly those vulnerabilities grow – and how severe future water shortages could become – still requires further study.

Studying those effects will be especially important, Hale said, as people have to adapt.

“If we are getting water at a time when we don’t need it and the mountains are no longer acting as natural water towers, how can we maintain seasonality of water use?” He said.

“It’s really going to require a re-evaluation of how we manage our water.”