Heavy overnight rains in Northern California left two people dead in a submerged car as authorities on Thursday urged residents of several Southern California mountain and canyon communities to voluntarily leave their homes because of possible mud and debris flows.
Firefighters in Millbrae, just south of San Francisco, were able to rescue a driver who had climbed atop his vehicle at a flooded underpass. But they were not able to reach people in another car, said San Mateo County Sheriff’s Detective Javier Acosta.
Acosta told the Mercury News in San Jose there was “overwhelming rain" rising rapidly in the underpass when firefighters responded to a call for help shortly before 6 a.m. It took several hours to drain the area, which is when authorities discovered the bodies. An investigation is underway.
Pedestrians carry umbrellas as they walk past a large holiday tree outside of the Chase Center in San Francisco, Wednesday, Dec. 22, 2021. Rain and snow showers fell on Northern California on Wednesday in the first wave of a wet weather pattern that is expected to spread throughout the state and last through Christmas into next week, forecasters said. (AP PhotoJeff Chiu)
The precautions for Southern California came as precipitation that had mostly been falling in Northern California this week spread throughout the state. Potentially heavy rain could start late Thursday in the southern part of the state.
The National Weather Service issued an advisory for minor flooding of roadways and low-lying areas in counties around San Francisco Bay and an avalanche warning was posted for eastern Sierra Nevada backcountry areas in Mono and Inyo counties.
Forecasters also issued a flood watch for areas east and southeast of Los Angeles starting Thursday evening because of possible heavy overnight rain fed by an atmospheric river, a long plume of moisture from the Pacific Ocean.
Evacuation warnings were issued by Orange County authorities for three canyons near a wildfire burn scar where rain last week unleashed muddy torrents. Warnings were also issued by San Bernardino County authorities for a half-dozen mountain areas.
Elsewhere, tire chains were required on several major routes through the Sierra Nevada and a stretch of coastal Highway 1 was closed south of Big Sur due to weather, according to the California Department of Transportation.
Periods of rain and snow were predicted for California through Christmas and into next week.