The storm was potent enough to push San Francisco’s cumulative rainfall total above normal for the first time this season, according to a local meteorologist, Jan Null.
Residents in Southern California awoke on Thursday to flinty gray skies, gusting winds and downpours. Flash flood warnings were posted for part of Los Angeles County near beaches and ports and on hillsides.
Ms. Schoenfeld of the National Weather Service said that residents of Palos Verdes Estates should be particularly vigilant. That is the area where homes perched atop seaside bluffs began slipping into a canyon last July, in a landslide that was blamed on the saturation of the soil by last winter’s storms.
In Long Beach, flooding forced the closure of a major freeway, bringing traffic in the area — which can induce headaches even in sunny weather — nearly to a standstill.