The first storm was forecast to linger into the weekend and produce an additional 6-12 inches of rainfall, the weather service said. An atmospheric river prompted a high-risk warning for excessive rainfall along the Northern California coast.

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.