Scientists define a new category of heat wave: ‘Snow eaters’

Scientists have a new name for a specific kind of heat wave: "snow eater." A recent study in the journal Science Advances defines these as stretches where temperatures stay above freezing both day and night for three to five days or more. That nonstop warmth can roughly double the rate snow melts, sending water rushing off mountains all at once instead of gradually through summer.

These events are showing up earlier in the year and covering more ground across the Western U.S. as the climate warms. Since the 1850s, the area affected has grown by about 40,000 square miles per century, and the first snow eater of the year now arrives roughly a month earlier per century. This spring, much of the West saw record-low snowpack, driven less by lack of precipitation than by unusually warm air across the region.

For homeowners, especially in mountain states like Utah, Colorado, and California, this matters mostly through downstream effects. Early, rapid snowmelt strains reservoirs and rivers that supply summer water, and dried-out mountain forests tied to thin snowpack have been linked to more intense wildfires, including ones that burned homes near Spokane, Washington, this year. Researchers are still studying whether snow eaters raise risks of avalanches or other mountain hazards. There's no new program or rebate tied to this finding, but it helps explain why water shortages and wildfire risk have felt more severe in parts of the West lately, and why that trend seems to be building rather than easing.