Rescue crews searched for anyone trapped, injured or dead in the onslaught that smashed homes and swept away cars. The fire destroyed 1,063 structures and damaged another 280 in Santa Barbara and Ventura Counties, particularly affecting the cities of Montecito and Carpinteria.
The area is home to a number of celebrities, including actor Rob Lowe, chat show host Ellen DeGeneres and TV personality and actor Oprah Winfrey.
Several major roads were buried beneath tons of mud, including the 101 Freeway.
With roads blocked, rescue crews used helicopters to pluck people from their rooftops.
Emergency personnel search through debris and damaged homes after a mudslide in Montecito, California on January 9.
"We've got multiple reports of rescuers falling through manholes that were covered with mud, swimming pools that were covered up with mud", said Anthony Buzzerio, a Los Angeles County fire battalion chief. The rain fell hard, officials say two to four inches fell in less than 30 minutes in some areas.
At least 300 houses were damaged in the Montecito area and many more were listed as "threatened". The torrent arrived suddenly and with a sound some likened to a freight train as water carrying rocks and trees washed away homes.