Only around 10 to 15 per cent of residents followed mandatory orders to evacuate after the torrential downpours overnight, a Santa Barbara Fire Department spokeswoman confirmed.

Authorities have said at least 13 people are dead and 25 reported injured as emergency services search for more survivors with dogs and helicopters.

The death toll is even higher than when the town of La Conceit was devastated by a major mudslide in 2005 claiming 10 lives.

County Fire Department spokesman Mike Eliason said: “It's going to be worse than anyone imagined for our area.

“Following our fire, this is the worst-case scenario.”

Oprah Winfrey has offered her support to the devastated community.

The TV host who is being touted as the next US President said: “What a day! Praying for our community again in Santa Barbara. Woke up to this blazing gas fire.

“Then swipe left to see how deep the mud is in my backyard. Helicopters rescuing my neighbours. Looking for missing persons. 13 lives lost.”

The Montecito area was worst hit after rain stripped hillsides of mud and debris which poured over streets and houses downing trees.

Reports claim it took just minutes for the pouring rain to overcome the hills and flood a creek.

Navy serviceman Tyler McManigal was informed by authorities that his father and brother had been swept away by flash flooding.

He said: “My father is being reported as missing right now.

"They found my brother probably three-quarters of a mile away, south of where the house is, on the 101 freeway.

"My brother is okay.”

Rescue workers are attempting to free people from cars and buildings, Mr Eliason said.

The County Fire Department spokesman warned that “waist-deep mud flows”, trees and damaged electrical lines were slowing rescue efforts.

Gas pipes in the area will be turned off amid safety fears, local authorities confirmed.

More to follow…