Photo: The Canadian Press

Firefighters kept a wall of flames from descending mountains into coastal neighbourhoods after a huge and destructive Southern California wildfire exploded in size, becoming the fifth largest in state history.

Thousands remained under evacuation orders Monday as the fire churned west through foothill areas of Carpinteria and Montecito, seaside Santa Barbara County towns about 75 miles (120 kilometres) northwest of Los Angeles. Much of the fire's rapid new growth occurred on the eastern and northern fronts into unoccupied areas of Los Padres National Forest, where the state's fourth largest fire burned a decade ago.

The blaze, which had already destroyed more than 750 buildings, burned six more in Carpinteria on Sunday, officials said. It's just 10 per cent contained after charring nearly 360 square miles (930 square kilometres) of dry brush and timber.

"We're still anxious. I'm not frightened yet," Carpinteria resident Roberta Lehtinen told KABC-TV. "I don't think it's going to come roaring down unless the winds kick up."

Forecasters predicted that dry winds that fanned several fires across the region for a week would begin to lose their power Monday. But the possibility of "unpredictable" gusts would keep firefighters on edge for days, Santa Barbara County Fire spokesman Mike Eliason said.

Santa Ana winds have long contributed to some of the region's most disastrous wildfires. They blow from the inland toward the Pacific Ocean, speeding up as they squeeze through mountain passes and canyons.

Containment increased on other major blazes in Los Angeles, Riverside and San Diego counties. Resources from those fires were diverted to the Santa Barbara foothills to combat the stubborn and enormous fire that started Dec. 4.

Despite the size and number of wildfires burning in the region, there has only been one confirmed death: The death of a 70-year-old woman, who crashed her car on an evacuation route, is attributed to the fire in Santa Paula, a small city where the Thomas Fire began.

Most of last week's fires were in places that burned in the past, including one in the ritzy Los Angeles neighbourhood of Bel-Air that burned six homes and another in the city's rugged foothills above the community of Sylmar and in Santa Paula.