This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A new study by researchers at Montana State University has found that heat waves substantially accelerate the melting rate of mountain snowpack; however, the resulting water doesn't necessarily produce an immediate increase in streamflow. The findings were published Oct. 1 in the paper "Heatwaves drive rapid snowmelt and disrupt streamflow in the western United States," in the journal Environmental Research Letters.
The researchers analyzed data collected from 2001 through 2024 at 823 Snow Telemetry, often called SNOTEL, stations across the western United States. Department of Agriculture's Natural Resources Conservation Service, the network measures snowpack, precipitation, temperature and other environmental conditions. "It's a very valuable data set, especially because it contains decades of observational records, providing statistically meaningful information," said Siwei He, assistant professor of civil engineering in MSU's Norm Asbjornson College of Engineering and co-author of the paper.
The researchers examined 24 years of snowpack and temperature observations, along with streamflow records from the U.S. Previous studies focused primarily on individual heat waves or smaller regions. This analysis used data collected from actual observations to investigate how heat waves affect snowmelt rate and streamflow across the western United States.
"Our data is not from a model. Our data comes from real-world observations," said Haonan Guo, a third-year civil engineering doctoral student at MSU and the lead author of the paper. For the purposes of this study, the researchers defined a heat wave as a period of three or more consecutive days with temperatures exceeding the 30-year historical average by more than twice the typical amount of temperature variation.
Of the 823 SNOTEL stations studied, at least 250 experienced a heat wave during the 24-year study period. At 98% of those affected stations, snow melted faster than the historical norm during heat waves. Across the observations, the likelihood of faster-than-normal snowmelt increased by roughly 80% during heat waves compared with normal conditions.
Of 168 headwater watersheds affected by heat waves, only 93—or around 55%—showed increased streamflow following heat waves. Faster melting, in other words, did not reliably produce an immediate surge in river flow. "We thought that was very interesting," He said.
Extract — continue reading at the source.
