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Atmospheric River Precipitation Enhanced by Climate Change: A Case Study of the Storm That Contributed to California’s Oroville Dam Crisis

Allison C. Michaelis, Alexander Gershunov, Alexander Weyant, Meredith A. Fish, Tamara Shulgina, F. Martin Ralph | February 9th, 2022

California’s reliance on precipitation from atmospheric rivers is expected to increase as our climate warms. Understanding how climate change is impacting this increasingly dominant mode of precipitation is vitally important for water-resource management throughout the state, across the North American West Coast, and for other similarly impacted regions. Our case study of an impactful atmospheric river from early February 2017 that contributed to the Oroville Dam crisis in Northern California, modeled under preindustrial, present-day, mid-, and late-21st century unabatedly warming environments, demonstrates an overwhelming increase in precipitation throughout the event. This particular storm was comprised of two distinct pulses, and while both pulses of the storm are enhanced in the warmer future epochs, the estimated precipitation increases are disproportionately higher for the second pulse due to larger increases in temperature and moisture. Our results therefore suggest that not all atmospheric rivers are similarly affected by climate change and point to specific directions for relevant future research.


atmospheric rivers, climate change, infrastructure, planning and management