At least 13 people are dead amid “waist-deep” mudslides in Southern California, where heavy rains triggered flooding, say officials.
Some 163 people have been taken to hospital. Twenty had “storm-related injuries” and four were critically hurt.
A group of up to 300 people are reportedly trapped in Romero Canyon, east of Santa Barbara.
Police said the scene “looked like a World War One battlefield”. The flooding and mudslides, affecting areas scorched by wildfires last month, have shut down more than 30 miles (48km) of the main coastal road.
Emergency services said a number of people were unaccounted for and they expected the number of deaths to rise.
Thousands fled the deluge and more than 50 rescues have been performed.
The hardest-hit homes were those that were not in the evacuation zone, officials say.
Heavy rain run-off caused a mudflow in the community of Montecito, where some homes were knocked off their foundations, said Santa Barbara County Fire Department spokesman Mike Eliason.
Boulders the size of small cars were rolling down hillsides and blocking roads, reports BBC News Los Angeles correspondent James Cook.
Among those taken to safety was a 14-year-old girl who had been trapped for hours in the ruins of her home.
— SBCFireInfo (@EliasonMike) January 9, 2018
This is not a river. This is the 101 freeway in my neighborhood right now. Montecito needs your love and support. pic.twitter.com/jRNCBrp4b5
— Ellen DeGeneres (@TheEllenShow) January 9, 2018
The fire department published a picture of the girl encased in mud as she was led to safety.
County Fire Captain Dave Zaniboni said that five people were found dead on Tuesday in Montecito and may have been killed as result of the storm.
The upmarket neighbourhood includes homes owned by celebrities such as actor Rob Lowe and chat show host Ellen DeGeneres.
Please see photos from the storm. If you witness significant mud, debris or fast flowing water, do not try to cross, or drive a vehicle through it and shelter in place. pic.twitter.com/RQNTHPc5z6
— City of Burbank (@BurbankCA) January 9, 2018
Flash flood / massive amounts of mud swept thru #montecito oaks neighborhood. Mud buckling doors trying to get in house. People on roofs. Power out. Power lines down all over #mudslide pic.twitter.com/1SvgOpqBTw
— Benjamin Hyatt (@caffeineben) January 9, 2018
Oprah Winfrey also has a property in Montecito that is reportedly worth nearly $90m (£66m).
The US Coast Guard has sent “multiple airships to support rescue operations” and warned the public not to fly drones, otherwise the flights would be grounded.
Thousands of California residents were asked to leave their homes on Monday for the second time in two months.
In Burbank, where waves of mud swept away vehicles, officials issued a mandatory evacuation order.
Did You Know?
Homes near burned areas can flood, even if they never have before. Regular homeowner's insurance does not protect against flood damage.
There is a 30-day waiting period before most flood insurance policies are effective. pic.twitter.com/YV62ehGpNA
— FEMA Region 9 (@femaregion9) January 8, 2018