At least 15 people have died after mudslides and flooding hit southern California.
Rescue workers are now searching for survivors.
More than 30 miles of the main coastal road have been closed and police said the scene “looked like a World War One battlefield”.
A group of 300 people are reportedly trapped in Romero Canyon neighborhood east of Santa Barbara, with rescue efforts due to resume at daybreak.
The death toll is expected to rise.
Up to now, more than 50 people have been rescued, but many places are still inaccessible. Several roads are closed, including the major Highway 101.
Some 163 people have been taken to hospital while other 20 had “storm-related injuries” and four were critically hurt.
The first rain in months caused mudslides when it hit ground that had been scorched by December’s huge wildfires.
According to specialists, after a wildfire, burned vegetation and charred soil create a water repellent layer which blocks water absorption. Together with the loss of vegetation, this leads to an increased risk of mudslides and floods.
The Federal Emergency Management Agency (FEMA) says the risk of flooding stays “significantly higher” for up to five years after a wildfire.
The National Weather Service said in a statement: “Recent burn areas will be especially vulnerable where dangerous mud and debris flows are possible.”
According to officials, in some places mud was waist-deep.
Thousands had to leave their homes, many for the second time in two months. The emergency services declared an exclusion zone, saying anyone moving around the area would be in the way of rescuers and would be subject to arrest.
Those who have stayed in the area have been warned to boil their tap water before drinking it.
Santa Barbara County Fire Department spokesman Mike Eliason said that heavy rain run-off caused a mudflow in the community of Montecito, where some homes were knocked off their foundations.
On January 9, County Fire Captain Dave Zaniboni said that five people were found dead in Montecito, possibly as a result of the storm.
The upmarket neighborhood includes homes owned by celebrities such as Rob Lowe, Ellen DeGeneres and Oprah Winfrey.
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.
According to the US National Oceanic and Atmospheric Administration, this comes after a record-setting year of $306 billion of weather and climate-related disaster costs in the US, with 2017 the third warmest year on record.
California has suffered severe drought in five out of six of the past years.
The Thomas fire slowly eclipsed previous record-setting blazes, finally overtaking the 2003 Cedar fire in San Diego County, which burned 273,246 acres.
It follows a series of deadly fires in the state’s wine country in October that burned more than 10,000 homes and killed more than 40 people.
The Thomas fire has destroyed more than 1,000 buildings and claimed the life of one firefighter – Cory Iverson, a father of one from San Diego whose wife was expecting another child.
It is now moving slower because of rain and less wind.
State fire agency Cal Fire says the Thomas fire is now 65% contained and expected to continue to slow. Controlled burns by firefighters may cause some temporary expansion, it said.
Seven of California’s 10 largest fires on record have occurred since 2000. Two were in the 1970s and the earliest was in 1932 – the Matilija fire which, like the Thomas fire, burned through Ventura County.
California Governor Jerry Brown has said that devastating wildfires fuelled by climate change are “the new normal”.
He said vast fires, such as the ones that have ravaged southern California in recent days, “could happen every year or every few years”.
“We’re facing a new reality in this state,” the governor said.
Jerry Brown made the comments after surveying the damage in Ventura County, north of Los Angeles.
Thousands of firefighters have been battling the fires since December 4.
Jerry Brown, a Democrat who has attacked the Trump administration’s stance on climate change, said: “We’re facing a new reality in this state, where fires threaten people’s lives, their properties, their neighborhoods, and of course billions and billions of dollars.
“With climate change, some scientists are saying southern California is literally burning up.”
The largest wildfire – known as the Thomas Fire – burned close to 150,000 acres, an area of land roughly the size of Chicago, Reuters reported.
On December 9, firefighters began to make progress in containing the blaze.
Southern California authorities have order the evacuation of 82,000 people from San Bernardino County after a wildfire broke in a mountain pass.
The blaze broke out on August 16 and has already engulfed about 15,000 acres of land.
Tens of thousands of homes are at risk from the so-called Blue Cut fire. A state of emergency has been declared.
Another fire, the Clayton, which broke out on August 13 in northern California, has destroyed 175 homes.
The Bluecut fire spread with great speed in the parched canyons around San Bernardino. At least a dozen buildings have already been engulfed.
Forest Service spokeswoman Lyn Sieliet said: “It is a very fast-moving fire, it has wind behind it.”
California Governor Jerry Brown has declared a state of emergency in San Bernardino County to bring in federal assistance.
The wildfire forced the closure of a stretch of Interstate 15, the main road between Las Vegas and Los Angeles area.
Some 700 firefighters are battling to control the blaze in the Cajon Pass. Its cause remains unknown.
The fire is now heading into the Mojave Desert.
The main communities forced to evacuate were the ski resort of Wrightwood and the desert town of Phelan.
Further north, the Clayton Fire in Lake County was now 35% contained, California’s department of forestry and fire protection said.
The authorities announced on August 16 that Damin Pashilk, 40, was facing 17 counts of arson and was suspected of involvement in numerous other fires in the Lake County area over the past year. He will appear in court on August 17.
A third fire, the Chimney, has affected 6,900 acres since August 13 and has destroyed about 40 buildings in central California.