Beyond Expectations: Investigating Anomalous 2022-23 Winter Weather Conditions and Water Resources Impacts in California
Au-delà des attentes : enquête sur les conditions météorologiques hivernales anormales de 2022-2023 et leurs répercussions sur les ressources en eau en Californie
Arellano, Claudia Jimenez ; Rouzegari, Nazak ; Dao, Vu ; Zadeh, Mohammad Bolboli ; Shearer, Eric ; Gorooh, Vesta Afzali ; Nguyen, Phu ; Hsu, Kuo-Lin ; Sorooshian, Soroosh
Année de publication
2025
The 2022-23 winter in the western United States, particularly in Southern California, experienced unusually wet and cold conditions, prompting vigilant water management. This study chronicles the water year, highlighting the challenges state water managers faced as California shifted from extreme drought to elevated flood risks due to an unprecedented "weather whiplash" and a subsequent record-setting snowpack. By analyzing precipitation and temperature data from 2002 to 2023, the research highlights the anomalous nature of these variables in California during this period. It focuses on the impacts of atmospheric rivers (ARs) due to their proven influence on seasonal precipitation patterns and intensities, examining their hydrologic impacts?specifically, snow water equivalent (SWE) in Sierra Nevada and reservoir storage?compared to other high precipitation years in California to gauge the effects of this atypical weather on water resources. The study reveals that Southern California's wintertime precipitation in 2022-23 was the highest in over two decades. Precipitation was closely linked to the occurrence of 11 moderate to strong ARs, which alleviated the state's drought conditions?94% of California was drought free by the end of the water year. Additionally, the mean maximum temperature was below the long-term average during spring and summer, decelerating snowpack melt and mitigating flood potential. Notably, 2022-23 saw the most significant increases in SWE and reservoir storage among the years analyzed. This research delves into the complex interplay between AR-driven precipitation, temperature, and snowpack, providing valuable insights into the precarious dynamics of California's regional hydrology with a real-world example.</div>
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