A combination of unusually warm winter weather across much of the Western United States and one of the worst snow droughts in decades has experts bracing for what could be a particularly intense wildfire season.
Snowpack is well below average for this time of year in nearly all Western states, and there is little time left to add snowpack and depth in the mountains before spring thaws begin. At the same time, higher-than-normal temperatures have led to a warmer and drier winter than many states are accustomed to, raising concerns about wildfire risk and water supplies.
“Snowpack in the Colorado mountains is the lowest it has been in more than 40 years,” said Russ Schumacher, director of the Colorado Climate Center at Colorado State University and state climatologist.
The October-February period in Colorado, a time when the state typically sees heavy snow accumulation in the mountains, was the warmest on record “by a wide margin,” Schumacher said. Fort Collins, where he resides, nearly doubled its previous record for days with temperatures above 60 degrees Fahrenheit in winter, going from 22 days to 43 so far.
As a result, the state has not seen the types of snowstorms that would normally be expected, and when storms have arrived, they have often dropped rain instead of snow, particularly at mid and lower elevations.
The problem extends beyond Colorado. Measurements of snow water equivalent (the amount of water stored in the snowpack) across the continental US West show that most of the region is well below average, with many basins at less than 50% of average for this time of year. Some are even around 25% of the average.
“When most places are at 50% of average or lower, that means there would be twice as much snow or more almost everywhere on the map,” said Noah Molotch, a geography professor at the University of Colorado at Boulder.
Molotch and his colleagues track snowpack conditions in the western continental U.S. and said this is one of the least snowy years he can remember. The only parts of the West with near-normal snow levels are the southern parts of the Sierra Nevada, a portion of northwestern Wyoming and small areas of northern Montana, Idaho and Washington, according to Molotch.
Everywhere else is experiencing a “pretty bad snow drought,” he said.
Studies have shown that snow droughts and earlier-than-usual melting of snow can contribute to more intense summer wildfire seasons. When there is much less snow cover than normal in forests and grasslands, or if snow melts earlier than usual during the year, vegetation has more time to dry out and become fuel for fires.
Already in Colorado, the Bluebell Fire that occurred over the weekend in Boulder prompted evacuation warnings and burned approximately 1.5 acres. The fire was quickly contained, but it offered a glimpse of how vulnerable the state could be once conditions become warmer, drier and windier.
“Intense fire weather is not necessarily in short supply these days,” Molotch said. “It’s pretty clear that these kinds of dry, snowy conditions set us up for potentially very intense wildfire seasons.”
Climate change is likely playing a role in these trends, Schumacher said. Although it may be difficult to directly link annual variations in snowfall to global warming (such attribution often requires years or decades of data to establish), climate change is known to increase the chances of above-average temperatures, even during winter.
“Precipitation deficits are harder to attribute to climate change, but in terms of really extreme temperatures, there is a clear connection to global warming,” he said.
The decline in snow cover in the mountains has dire consequences for water supplies in the West. As snow accumulated during the winter months melts during the spring and summer, it feeds rivers and streams that provide water for cities, agriculture, and hydroelectric dams.
“It’s the lifeline of our water supply,” Molotch said.
Without robust levels of snowpack, reservoirs across the Western United States will not be adequately replenished.
“The story is not just about Colorado, although the Colorado River Basin is in a pretty dire situation because it is a basin that is already over-allocated and the federal government is already facing difficult decisions about reducing allocations in the basin,” Molotch said.
The weeks leading up to spring may produce significant snowfall in parts of the West, including Colorado and Utah, but so far forecasts for the coming weeks don’t look promising.
Schumacher said he begins with an optimistic outlook each winter, but that is leading to resignation.
“We are here at the beginning of March and, unfortunately, there is not much time left for things to change,” he said. “The hope now is that instead of being a historically bad year, it ends up being just a bad year.”
