August 17, 2026
Heat Wave Update | August 17, 2026 | 2 min read
Researchers have finally put a name to a heat wave pattern that has been quietly reshaping the West's water supply: the "snow-eater." A study published this month shows how these events nearly double snowmelt rates, and this March's episode helps explain why so much of the West has slipped into drought. Here's what defines a snow-eater heat wave and why it matters this summer.
In a study published August 5 in the journal Science Advances, researchers defined snow-eater heat waves for the first time: sustained temperatures at least 6°C (about 11°F) above normal for three or more days, staying above freezing even overnight.
That overnight warmth is what sets these events apart from an ordinary warm spell. It keeps the snowpack from refreezing after dark, so instead of melting only at the surface, the entire snowpack "ripens" and drains away fast.
The numbers tell the story. On snow-eater days, snowmelt jumps to roughly 17 millimeters of water per day, compared with about 9 millimeters per day during a normal March-to-July melt season.
The name echoes the "snow-eating" chinooks, warm mountain winds that western communities have talked about since at least the 1880s. But this is the first time the pattern has been formally defined and tracked using historical weather data and modeling.
A record-shattering heat dome settled over the western United States in mid-March, pushing summer-like warmth high into the mountains. It arrived after an already warm, dry winter had left the snowpack thin to begin with. The result was a sudden, early, and rapid melt.
By April 1, the date snowpack water content usually peaks, the amount of water stored in what remained of the western snowpack was the lowest ever recorded for that date.
Mountain snowpack normally works like a slow-release water source, feeding rivers and reservoirs gradually through spring and summer. When it melts weeks early, that buffer vanishes before the dry season even begins.
The fallout is already clear. Large parts of the West now face severe to extreme drought, the Colorado River System is sitting at some of its lowest levels on record, and wildfires in the Northwest have burned millions of acres this year. The Intermountain West, including Nevada, Idaho, and Utah, took an especially hard hit. Drought had already gripped the region through most of the winter before the March heat wave stripped away what little snowpack was left.
"It feels like a monster came and just in the middle of the night, took a bite out of a snowpack," said LaPlante, a journalist and climate scientist at Utah State University.
Almost certainly. The study, co-authored by Dan McEvoy of the Desert Research Institute and Ben Hatchett of Colorado State University's Cooperative Institute for Research in the Atmosphere, found that spring and early-summer heat waves in the western U.S. have nearly doubled in frequency and intensity since the mid-1990s. Some of the largest snow-eater melt events on record hit during major Western droughts, including California's 2013–2015 dry spell.
For now, the research covers only the western United States, but scientists suspect the same pattern plays out in other snow-dependent regions that haven't been studied yet. Researchers are also digging into whether snow-eater events raise the risk of avalanches, glacial collapse, and permafrost melt.
Get ahead of a dry, dusty summer
A thin snowpack year usually means drier soil, more airborne dust, and a longer wildfire season, and all of that puts extra strain on your home's HVAC system. A few steps worth taking now:
Sources: Science Advances, Grist, Nevada Current, Courthouse News Service, KVNF.
