The number of confirmed deaths from flooding and mudslides in Montecito, north west of Los Angeles, is currently standing at 17, as Californian authorities on Wednesday are stepping up their search for at least 20 missing persons.

Santa Barbara County's sheriff Bill Brown said that the rescue teams have worked tirelessly since Tuesday night searching for the missing, adding that 28 people were injured in the event.

"While we hope it will not, we expect that this number will increase as we continue to look for people who are still missing and unaccounted for," the sheriff said at a press conference.

The mudslides struck an area that suffered already in last month's Thomas wildfire, and was spurred by torrential downpours that dropped nearly an inch (2.54 cm) of rain in less than 15 minutes.

The Santa Barbara County Fire Department (SBCFD) reported Wednesday that nearly 100 homes were destroyed and 300 others were damaged.

In some of the areas flooded Tuesday, the authorities had ordered evacuation and recommended that the residents move to high areas, although many did not consider the risk to be so serious and decided to stay in their homes.

The mudslides in some areas reached a height of five feet (1.5 meters), a spokesperson for SBCFD told EFE, while more than 500 firefighters are involved in rescue operations which managed to save dozens of people by helicopter and many more by land.

"Residents are allowed to shelter-in-place in their homes but will not be allowed to move about the area. Persons failing to abide by the order are subject to arrest for this misdemeanor violation," the Santa Barbara County Joint Information Center warned.

Floods and mudslides also inundated a part of Highway 101, forcing the Highway Patrol to shut down a 50-kilometer stretch between Santa Barbara and Ventura, including the part that runs through Montecito, until Thursday night.

The affected area is one of California's tourist attractions and the price of houses in the area ranges between $1.4 and $4 million, some of them are owned by celebrities, including TV hosts Ellen DeGeneres and Oprah Winfrey and actor Rob Lowe, among others.

All of them will be without clean water and electricity "for a long period of time," the Santa Barbara County Office of Emergency Management announced Wednesday.