UCLA researchers predict more intense atmospheric rivers for California, with consequences for flooding and water supply

California can expect more intense levels of precipitation from atmospheric rivers as the climate changes, a team of UCLA researchers have found.

In a study published in Science Advances, the researchers quantified projected changes in precipitation driven by extreme atmospheric rivers in the Sierra Nevada mountains. Atmospheric rivers are long corridors of water vapor traveling from the Pacific Ocean to California that provide 20-50% of the state’s water in a given year. The Sierra Nevadas provide about 23 million Californians with water. 

Researchers used a high-resolution atmospheric model commonly used in making day-to-day weather forecasts to simulate future storms in detail. The simulations project a 10% to 40% increase in total accumulated precipitation across the southern, western and northern Sierra Nevadas.

The study adds to an increasing body of research that suggests California will face more frequent and intense storms in the near future. The findings have implications for water and flood management practices in the state.  

Study Authors:

Xinying Huang, postdoctoral scholar, UCLA Institute of the Environment and Sustainability

Daniel L. Swain, climate scientist, UCLA Institute of the Environment and Sustainability

Alex D. Hall, professor, UCLA Department of Atmospheric and Oceanic Sciences

More information:

Read a detailed summary of the study by lead author Daniel Swain.

Read the full report in Science Advances.

Explore related research in the Research Portal.

The study was funded in part by the Sustainable LA Grand Challenge. Additional funders include the UCLA Institute of the Environment and Sustainability, the Capacity Center for Climate and Weather Extremes at the National Center for Atmospheric Research, and The Nature Conservancy of California.