Atmospheric Rivers (ARs) are long, narrow-shaped streams of water - and lots of it. Nicknamed "Pineapple Express" they form when winds over the Pacific draw moisture from the warm, moist air over the tropics and channel it toward the West Coast. When this ribbon of moisture meets mountains, it is forced upward, cooling it and turning its water into immense quantities of rain and snow.

Learn more on the National Oceanic and Atmospheric Administration (NOAA) website:
https://www.noaa.gov/stories/what-are-atmospheric-rivers

 LEARN MORE:

• CA DWR - Atmospheric Rivers and Their Impact on California's Reservoirs, 10/28/20
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