More snow melting from mountains earlier in year due to climate change: study
TORONTO -- Climate change is causing more snow to melt in the mountains, which could impact agriculture and increase the risk of flooding and wildfires, according to a study published Monday in Nature Climate Change.
Researchers based at the University of Colorado Boulder examined 40 years of data from 1,065 automated stations in western Canada and the United States and found that more snow is melting earlier in the year.
At 42 per cent of the stations, researchers found that the percentage of annual melt that occurs before April 1 is increasing by 3.5 per cent per decade.
Researchers say the increasing number of stations with earlier snowmelt can be explained by increasing temperatures. In 2009, only 12 per cent of stations experienced significant warming. By 2019, the figure was 46 per cent.
“Particularly in cold mountain environments, snow accumulates over the winter—it grows and grows—and gets to a point where it reaches a maximum depth, before melt starts in the spring,” said lead study author Keith Musselman in a news release.
In western North America, snowmelt is the primary source of water and an increase in snowmelt has serious ecological implications.
A shift in the snowmelt to the spring rather than the summer can have an impact on agriculture and food security. Farmers rely on the timing of the runoff forecasts to plan irrigation. Less snowmelt in the summer can also increase the risk of wildfires.
The surface runoff from the melting snow ends up in the soil system, which can reduce the soil's buffering capacity and can make the terrain more prone to flooding.
“That slow trickle of meltwater that reliably occurs over the dry season is something that we have built our entire water infrastructure on in the West,” said Musselman. “We rely very heavily on that water that comes down our rivers and streams in the warm season of July and August.”
The snow monitoring stations have long been an underused source of data. This is the first study of its kind to examine all 1,065 stations in western North America.
“These automated stations can be really helpful to understand potential climate change impacts on our resources,” said Musselman. “Their observations are consistent with what our climate models are suggesting will continue to happen.”