A new research initiative is investigating how late spring and early summer heat waves accelerate snowpack depletion and influence the magnitude of snow drought conditions across the Western United States, according to a Drought.gov announcement on Aug. 21, 2026. The study follows earlier reporting from Grist on Aug. 12, 2026, which identified these specific temperature events as "snow eaters" that can roughly double the rate of snowmelt.
Researching Snowmelt and Runoff
The research, supported by the National Integrated Drought Information System (NIDIS), aims to understand how heat waves influence snow conditions and trigger the onset of snow drought conditions. The project will specifically examine the relative influence of heat wave-induced snowpack changes on runoff, streamflow variability, soil moisture, and downstream reservoir conditions.
Principal investigator Laurie Huning of California State University, Long Beach, is leading the project alongside co-principal investigators Alan Rhoades of the Lawrence Berkeley National Laboratory and Dan McEvoy of the Desert Research Institute. The research team will utilize several NOAA data products, including the National Water Model and the recently updated Twentieth Century Reanalysis Version 3, to analyze how snowmelt season heat wave events are represented across various scales.
Defining Snow Eater Heat Waves
The term "snow eater" refers to heat waves marked by unusually high temperatures in the spring and early summer. According to research published in the journal Science Advances, these events occur when temperatures stay above freezing during both the day and night for typically three to five days.
Matthew LaPlante, a climate scientist at Utah State University, noted that these events can cause snow levels to drop significantly overnight. As previously reported by Grist on Aug. 12, 2026, these heat waves can roughly double the rate of snowmelt, potentially causing flooding and creating challenges for managing water resources.
Expanding Regional Impact
The impact of these heat waves has expanded over time. Research indicates that since the 1850s, the area affected by snow eaters has increased by an average of approximately 40,000 square miles per century. Additionally, the first snow eater of a season has been arriving about one month earlier per century as the climate warms.
Noah Molotch, a professor of geography at the University of Colorado Boulder, noted that solar radiation can amplify the effects of heat waves on snowmelt. As snow crystals warm, they lose their structure and ability to reflect light, causing the snowpack to absorb more sunlight and melt faster in a process Molotch described as a "snowball effect."
Wildfire and Safety Risks
The rapid melting of snowpack has direct implications for wildfire intensity and frequency. Molotch stated that drought stress for mountain forests in the Western U.S. is heavily dictated by the snow that accumulates in winter and melts through the spring and summer, creating a connection between water availability and wildfire intensity.
In addition to wildfire risks, Ben Hatchett, a scientist at Colorado State University's Cooperative Institute for Research in the Atmosphere, stated that snow-eater heat waves may pose risks to hikers, skiers, and others near mountains. Hatchett noted these events could be linked to hazards such as avalanches, permafrost melt, and glacial collapses, though scientists are still investigating those specific connections.
Implications for Water Management
The ability to better predict snowpack changes is critical for water management. Hatchett explained that when water is released early due to rapid melting, it must be managed as a hazard at reservoirs and along rivers and streams rather than a resource for the drier summer months.
The research project, which spans from September 1, 2023, to August 31, 2026, aims to provide an open-access archive of project analysis scripts and catalogs derived from NOAA data products to assist with drought forecasting and management.
