LOS ANGELES -- The most powerful El Nino storm yet this week pushed onto the California coast Wednesday as police and outreach teams kept an eye on Los Angeles riverbeds where thousands of homeless people live and would be vulnerable to flash flooding.
Driving rain inundated the San Francisco Bay Area during the morning commute, causing nearly two dozen crashes, toppling trees and flooding streets and streams.
The storm pushed southward toward Southern California with strong thunderstorms and pounding surf with waves topping 10 feet.
It's the latest in a series of El Nino storms that has drenched California and the desert Southwest as it heads toward the Gulf Coast.
The latest system is packing colder temperatures, stronger winds and heavier rainfall than the previous ones that have lined up since the weekend and brought much-needed rain to the drought-stricken state.
In all, the current storm could dump as much as three inches of rain in coastal and valley areas and up to four inches at higher elevations, said NWS meteorologist Curt Kaplan.
Another less powerful El Nino storm was right behind and expected to hit land Thursday,
Authorities have spent days getting homeless people from low-lying areas along the Los Angeles River. Shuttles were available to shelters that had room for as many as 6,000 beds, Los Angeles Mayor Eric Garcetti said.
Los Angeles officials have mapped homeless encampments for the first time as they try to contact as many people as possible. Police were prepared to temporarily detain people who were illegally camped along the Los Angeles River but refused to move.
"We're not going to charge them with things," Garcetti said. "But we will use the force of law -- there is law on the books that they can't be there."
Motorists in mountain areas were warned that blizzard conditions with wind gusts reaching 60 mph were possible above 4,000 feet. Flash flooding and flows of mud and debris remained a worry in foothill neighbourhoods beneath areas left barren by wildfires.
The National Weather Service said a record 1.42 inches of rain fell Tuesday at Los Angeles International Airport as a previous storm passed through the region.
In Orange County, south of Los Angeles, a homeless man in his 40s was swept off his feet by swift waters and washed nearly a mile down Brea Creek in Buena Park before he pulled himself out, fire officials said. He was treated at a hospital for scraped feet and arms.
San Diego fire-rescue crews responded to 75 calls in three hours. Most dealt with cars in flooded intersections, including instances in which a woman and her dog were pulled to safety and a family of four was rescued from their vehicle as waters swiftly rose.
Despite the potential for flooding and mudslides, the wet weather was welcome news for a state suffering from a severe drought. But officials warned residents against abandoning conservation efforts and reverting to wasteful water-use habits.
California's water deficit is so deep after four years of drought that a steady parade of storms will be needed for years to come, said Mike Anderson, climatologist for the state Department of Water Resources.
The current El Nino system -- a natural warming of the central Pacific Ocean that interacts with the atmosphere and changes weather worldwide -- has tied a system in 1997-1998 as the strongest on record, the National Oceanic and Atmospheric Administration's Climate Prediction Center said.
Associated Press writers John Antczak in Los Angeles, Kristin J. Bender in San Francisco, Scott Smith in Fresno, California, and Seth Borenstein in Washington contributed to this report.
