Forecasters in the US have warned that floods are still possible following one of the wettest storms in southern California’s history.
The slow-moving storm that parked itself over the region on Monday, dumping a record amount of rain on parts of Los Angeles, could linger into Wednesday, the National Weather Service said.
Scattered showers and some possible thunderstorms will bring light to moderate rain, but there is still the threat that many places could see brief, fierce downpours dumping up to an inch of rain in an hour.
Authorities warned people to remain on high alert and most of southern California remained under flood watches. Swollen and fast-moving creeks and rivers “increase the risk for drowning and the need for swift water rescues”, the weather service said.
The storm ploughed through northern California over the weekend, killing three people who were crushed by falling trees, then lingered over the south. It was the second storm fuelled by an atmospheric river to hit the state over recent days.
On Monday, it saw Los Angeles deluged with rain, sending mud and boulders down hillsides dotted with multimillion-dollar homes while people living in homeless encampments in many parts of the city scrambled for safety.
Near the Hollywood Hills, floodwaters carried mud, rocks and household objects downhill through Studio City, city officials said. Sixteen people were evacuated.
“It looks like a river that’s been here for years,” said Keki Mingus, whose neighbours’ homes were damaged. “I’ve never seen anything like it.”
Drake Livingston, who lives in the Beverly Crest neighbourhood, was watching a movie around midnight when a friend alerted him to flooding.
“We looked outside and there’s a foot-and-a-half of running water, and it starts seeping through the doors,” said Mr Livingston, whose car was found submerged in mud on Monday morning.
Downtown Los Angeles received nearly 7in of rain by Monday night, nearly half the yearly average of 14.25in. It was already the third wettest two-day period since 1877, the service said.
The danger was not over despite a projected dip in the rainfall, warned Ariel Cohen, the meteorologist in charge of the National Weather Service bureau in Los Angeles.
“The ground is extremely saturated, supersaturated,” he said at a Monday afternoon news conference. “It’s not able to hold any additional water before sliding. It’s not going to take much rain for additional landslides, mudslides, rockslides and other debris flows to occur.”
In LA, an evacuation order remained in place for some residents of a canyon area that was scarred by a fire in 2022. The area was at increased risk of mud and debris flows because the area was burned bare of brush and trees that could hold it back, authorities said.
The Los Angeles Fire Department said 1,000 firefighters had dealt with more than 300 mudslides in addition to more than 100 reports of flooding and rescues of motorists stranded in vehicles on inundated roads.
Shelters added beds for the city’s homeless population of nearly 75,000 people.
Crews rescued people from swift-moving water in various parts of southern California, including 16 people and five cats in Los Angeles County alone, authorities said.
About an hour’s drive east of Los Angeles, two homeless people were rescued on Monday after spending the night on a small island in the Santa Ana River in San Bernardino.
Over the weekend, the storm inundated streets and brought down trees and prompted water rescues in the San Francisco Bay area.
Among those who died were two men killed by fallen trees on Sunday in Carmichael, a suburb of Sacramento, and in Boulder Creek in Santa Cruz County. Police were investigating the death of another man in Yuba City, about 100 miles north-east of San Francisco, who was found under a redwood tree in his garden.
Governor Gavin Newsom declared a state of emergency for most of coastal southern California and on Monday, President Joe Biden promised to provide any needed federal help.
“We’ll get any help on the way as soon as you guys request it,” he told Los Angeles mayor Karen Bass in a telephone call.