UCI Climate Researchers Predict Winter Storms Will Be More Intense and Concentrated

Striated/layered shelf cloud in Charlton, Massachusetts, on July 2, 2022. Photo courtesy of Will y theweatherguy473737/ Creative Commons Attribution-Share Alike 4.0 International license.

June 10, 2025 - UC Irvine civil and environmental engineering researchers have found that future winter storms will produce more rain in less time and over smaller areas than they have in the past. The study, published in the American Meteorological Society’s Journal of Climate, analyzed simulations of future climate scenarios over the Western U.S. and Canada. 

These simulations, run on a supercomputer at the National Energy Research Scientific Computing Center (NERSC), were at a higher resolution than most previous simulations of future climate situations.

“These model predictions imply an increased risk of rapid flooding in small basins,” said lead author Clement Guilloteau, UCI associate research specialist in civil and environmental engineering. “They also suggest that predicting several hours ahead the time and location at which a storm will produce maximum rainfall may become more challenging in the future.”

Maps showing the rate of change for storm average precipitation intensity and average storm size between the 1981-2020 period and the 2041-2080 period in Western U.S. and Canada.

Researchers compared the simulated future storm characteristics (from 2041-2080) to historical climate records (1981-2020). In addition to producing a higher rainfall volume on average, storms in the future will be more concentrated in space and time, meaning that a very high volume of rain could occur over just a few hours and over a relatively small area.

According to Guilloteau, increased air temperatures in the future will be associated with increased air moisture. Warm moist air provides energy for convective storms to develop. More available energy leads to more intense ascending winds and higher altitude of the storm top. As the convective storms get more intense and taller, they also tend to shrink horizontally. As a consequence, the area on the ground covered by the most intense part of the storm gets smaller.

Others involved in the research include UCI Distinguished Professor Efi Foufoula-Georgiou, and collaborators Xiaodong Chen and L. Ruby Leung from the Pacific Northwest National Laboratory.

–  Lori Brandt

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