The storm flooded major roads in the Bay Area of northern California, before avalanches of mud and debris blocked part of the Pacific Coast Highway in Ventura County in the south of the state, the National Weather Service said.
Spokesman Stuart Seto said heavy rain was falling in Ventura County as well as western Los Angeles County, where possible flash flooding remained a concern. The weight of the storm was expected to move into the Los Angeles area later, Mr Seto added.
More than 100 homes were evacuated after the rain triggered mudslides in two southern California areas.
Ventura County Sheriff’s Office said mandatory evacuations had been ordered for 124 homes in Camarillo Springs, about 50 miles north west of Los Angeles. No injuries were reported in the area burned by a blaze last year.
The Red Cross said 40 people displaced by the slide had gone to an evacuation centre, and two were taken to hospital.
Farther east in Glendora, the site of a devastating fire in January, police said debris flow was sending golf ball and brick-sized rocks down streets. A spokesman said five people were using an evacuation centre but the exact number of people who fled their homes was not available.
The storm’s powerful winds caused power outages around Santa Barbara and other parts of the coast, and forecasters predicted the winds would continue to pick up speed.
On Thursday, torrential rains hit the San Francisco Bay Area and the surrounding region, pushing waterways towards flood stage, toppling trees and cutting power to thousands.
In Oregon, a falling tree killed a homeless man sleeping on a trail, and a teenage boy died after a large tree fell on the vehicle in which he was riding.