California Braces for Flooding as First Storm in Series of Atmospheric Rivers Hits Northern California

California is bracing for flooding as a new storm system brings heavy rain to Northern California on Friday. This storm is the first in a series of atmospheric rivers, known as a “Pineapple Express” because it brings warm subtropical moisture from near Hawaii.

The flood threat comes from the combination of rain and the melting of lower parts of the huge snowpack built in California’s mountains by nine atmospheric rivers early in the winter and later storms fueled by a blast of arctic air.

Forecasters warned that widespread heavy rain would raise the threat of flooding in a state still digging out from earlier storms. The heart of the atmospheric river is expected to arrive late in the day, with rain already spreading across the north by early afternoon.

The National Weather Service issued a flash flood watch for the entire Bay Area, with the heaviest rain expected in the North Bay and Santa Cruz Mountains. The watch will remain in effect until Saturday evening.

The California Office of Emergency Services is urging residents to be prepared for potential flooding. Residents are encouraged to clear debris from storm drains and gutters, secure outdoor furniture and other items, and be aware of the potential for mudslides and debris flows in areas recently burned by wildfires.