An aerial view shows a Los Angeles home destroyed by a mudslide Photo: AFP
By Ido Vock and Max Matza for the BBC
California authorities are conducting rescue operations after a deadly winter storm caused landslides and flooding.
The operations are underway one day after Los Angeles recorded its rainiest day ever. On Monday (PST), the mayor declared a state of emergency.
About six months of rain is expected to fall in Los Angeles and its surrounding areas in just 24 hours on Monday.
The "atmospheric rivers" causing the storms have already brought rain, wind and snow to swathes of California.
The storm has been linked to the death of one man in Sacramento Valley, who died on Sunday after a tree fell on him due to fierce winds. Another person was killed in a separate incident when a tree fell onto a home in Santa Cruz County.
Officials have issued evacuation orders for some hilly neighbourhoods in southern California, including in Los Angeles and Santa Barbara.
"It is vital now more than ever, stay safe and off the roads," LA Mayor Karen Bass said on Monday as she announced a state of emergency.
"Only leave your house if it is absolutely necessary."
A person walks to the edge of the raging Los Angeles River as the second and more powerful of two atmospheric river storms inundates Los Angeles, California, on 5 February, 2024. Photo: AFP
A state of emergency has also been declared by the governor in eight state counties.
Mudslides and debris flows have been reported. On Sunday, 16 residents were forced from their Hollywood Hills homes after mudslides flowed through houses, knocking buildings off their foundations and rupturing gas lines.
Witnesses have reported seeing refrigerators and pianos flowing through streets amid the debris.
Damage has also been reported in the upscale Bel Air and Beverly Hills neighbourhoods of LA.
"It sounded like lightning," Beverly Glen resident Dave Christensen told KTLA-TV.
"When I went out to... see what was there, I thought I saw a water heater where the house used to be and sure enough it was because the house had slid off the hill and into the road."
Drivers stranded by flooding in Los Angeles and San Bernardino County had to be helped by rescuers.
Streets flood in Santa Barbara, California, during the powerful storm. Photo: AFP
A father, mother and daughter were forced out of their car early on Monday and were able to climb into a tree to escape the rising flood waters, according to San Bernardino County Fire.
Fire rescue crews on the coast came to the aid of 19 boaters who became stranded on rocks near the Long Beach breakwater after their 50-ft sail boat lost its mast in gale force winds.
Lifeguards sent rescue swimmers to make contact with the group, who were then assisted into rescue boats with only one person suffering non-life threatening injuries.
Strong winds of up to 70mph (112kmph) have also caused power outages and downed trees, though winds should decrease significantly by Monday night.
It follows what has already been a record-setting day for the state. The National Weather Service (NWS) said that on Sunday, 4.1in (10.4 cm) of rainfall fell in downtown Los Angeles, surpassing the previous record of 2.5in set in 1927.
Nearly half a million people were without power on Monday morning as the storm knocked out electricity networks.
The storm has also forced schools in Malibu to close as some staff were not able to get there due to road flooding and closures.
Police in Los Angeles have reported that several homes and vehicles were damaged by debris flow and landslides, and have said that they are seeing a major increase in traffic accidents.
"Very heavy" snows would continue in the Sierra Nevada mountains, the NWS said, rendering travel "dangerous to impossible".
Snow falls in the Grant Grove of giant sequoia trees in Kings Canyon National Park, California, during the atmospheric river storm. Photo: AFP
What are atmospheric rivers?
The storm is due to an "atmospheric river" effect, caused by airborne currents of dense moisture.
Atmospheric rivers are a phenomenon in which water evaporates into the air and is carried along by the wind, forming long currents that flow in the sky like rivers flow on land.
A first atmospheric river hit California last week. The renewed bout of bad weather is caused by a second.
In a statement declaring the state of emergency in eight counties, including Los Angeles and Orange, Governor Gavin Newsom said: "This is a serious storm with dangerous and potentially life-threatening impacts.
"California is ready with a record number of emergency assets on the ground to respond to the impacts of this storm."
Two other counties have declared their own states of emergency.