Lake Oroville in California last month saw one of the biggest water-level changes the reservoir has ever experienced in November. A bomb cyclone brought dangerous weather conditions across the Pacific Northwest last month, causing power outages for more than a half-million people and killing at least two. Several atmospheric rivers pummeled California at about the same time. A bomb cyclone occurs when a storm’s pressure drops quickly, which intensifies the storm and ramps up wind gusts. Atmospheric rivers are a “long, narrow region in the atmosphere—like rivers in the sky—that transport most of the water vapor outside of the tropics,” according to the National Oceanic and Atmospheric Administration. The deluge contributed to a sudden rise in several California reservoirs, including Lake Oroville, the state’s second-largest reservoir.

Other water supply articles:

• KRCR: Shasta Dam to receive crucial upgrades as part of $849M Western US water initiative
• U.S. Department of Interior news release: Biden-Harris Administration announces nearly $850 million to revitalize aging water infrastructure, advance drought resilience
• The Hill: California cuts back on water deliveries, anticipating dry year ahead
• ABC 10 (Sacramento): After stormy November, Northern California’s forecast has turned meek