The so-called Thomas fire is only 15 per cent contained, now threatening the city of Santa Barbara and the nearby coastal town of Carpinteria, making it one of the worst wildfires in California history.
It has already destroyed 600 structures and scorched 173,000 acres (70,000 hectares), the authorities say, with the state's governor saying the fires had already caused unprecedented damage in the most populous US state.
"Praying for my town. Fires closing in. Firefighters making brave stands. Could go either way. Packing to evacuate now," the actor Rob Lowe, who lives in Santa Barbara, wrote on Twitter.
A photo posted by Santa Barbara police on Sunday morning showed a wall of flames several yards (meters) high very close to buildings in Carpinteria.
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Evacuation orders were issued overnight for some parts of Carpinteria close to Los Padres National Forest, where fire was raging.
Conditions remained very dry in southern California, according to the National Weather Service, but strong winds that have fueled the fires for much of the week have eased significantly.
It said "critical fire weather conditions will wane Sunday night" but that dangers would persist through most of the coming week.
"Firefighters continue to improve and increase the containment lines," helped by the weather, said the state agency Calfire.
Fire crews search homes destroyed in the Rancho Monserate Country Club community, California (AAP) Source: AAP
Returning home
After a five-day siege, some Californians were finally able to return home to inspect the damage wrought by the wildfires, which together have forced hundreds of thousands of people to flee and destroyed more than 850 structures, including multimillion-dollar mansions.
Cindy Nava, from the town of Sylmar, was one of those returning home -- or to what once was her home.
"Oh, my God, there's nothing, nothing, nothing," she sobbed, according to the Univision website. "What are we going to do?"
Despite the intensity of the fires that raged on multiple fronts -- stretching from areas north of Los Angeles down to the San Diego region -- authorities have reported only one fatality.
US President Donald Trump has issued a state of emergency for California, authorizing the release of federal funds.
The week's infernos capped California's deadliest year ever for wildfires. More than 40 people died in October when fires swept through the state's wine-producing counties north of San Francisco.
In a television interview on Sunday, California Governor Jerry Brown said that climate change meant that the state was becoming increasingly vulnerable and that wildfires were becoming the new normal in some parts.
"The fire season used to be a few months in the summer, now it's almost year-long. These fires are unprecedented. We've never seen anything like it.
"Scientists are telling us: 'This is the kind of stuff that's going to happen'. And we got to deal with it."
Brown has been one of the most vocal critics of Trump's decision to pull the United States out of the Paris accord on global warming and he renewed his attacks on the administration over its attitude towards climate change.
"Nature is not a political game. Nature is the ground on which we stand, it's the air which we breathe.
"The truth of the case is that there's too much carbon being emitted, that heat-trapping gasses are building up, the planet is warming and all hell is breaking loose."
