Trees are seen through the haze at the burned-out Vista del Mar Hospital after the Thomas wildfire swept through Ventura, California
Los Angeles (AFP) - Local emergency officials warned of powerful winds on Thursday that will feed wildfires raging in Los Angeles, threatening multi-million dollar mansions with blazes that have already forced more than 200,000 people to flee.
Authorities issued a "purple" alert -- never used before -- because of the extreme danger, warning that winds could reach 80 miles an hour (128 kilometers an hour), severely limiting firefighting efforts.
"As expected winds have increased dramatically," Cal Fire, the agency responsible for fire protection in the state, said on Twitter. "Stay alert and prepared in case of evacuations. If you feel unsafe, evacuate."
The flames have swallowed about 80,000 acres (32,000 hectares) in just over a day since the "Thomas" fire, currently the state's largest, broke out, leaving at least one person dead in an area about 45 minutes' drive from downtown LA.
High winds caused another wave of wildfires to erupt on Tuesday night, including one in Los Angeles' affluent Bel-Air neighborhood.
The area battled gridlocked traffic as residents fled ash and smoke that churned over the smoldering hillside in the second-largest US city.
Fire crews worked to save luxury homes threatened by the flames.
- Celebrities evacuated -
Los Angeles Mayor Eric Garcetti said more than 230,000 people had been forced from their homes in Los Angeles and Ventura counties.
"Very strong winds" blowing from the northeast to the southwest were causing the fire to balloon, he said, warning Angelenos to be ready to flee at a moment's notice.
In Bel-Air, that's exactly what they did.
The "Skirball" fire ignited Wednesday morning and quickly grew to engulf about 150 acres around the district, home to celebrities and billionaires including SpaceX CEO Elon Musk and pop superstar Beyonce.
Police knocked on doors and used loudspeakers to make sure everybody had left their mansions.
"They told even us to leave," one of the officers said.
Among the last to go was Evan Kleib, a bearded photographer, locking his door. He put his camera and his dogs in his vintage burgundy car and left the home where he has lived for several years, its fate uncertain.
US media reported that the Bel-Air Moraga Estate of media tycoon Rupert Murdoch, which contains a vineyard, was threatened by the wildfire.
The singer Lionel Richie cancelled a concert to help his ex-wife flee the area, while comedian Chelsea Handler and designer Adrienne Maloof were among celebrities tweeting that they had to evacuate.
Among those evacuated was model Chrissy Teigen, wife of singer John Legend. "Never thought I'd get to actually play what I thought was a hypothetical game of what would you grab if there were a fire," Teigen wrote on Twitter.
"We are fine and we will be fine. thinking of everyone else affected and continuing my lifelong intense love of firefighters," she added.
Forecasters predicted that winds could cause fires to spread further, threatening more upscale homes and the acclaimed Getty Center museum.
The "Skirball" fire -- near a cultural center of the same name -- also prompted authorities to close the 405 Freeway, a major commuting corridor.
Residents of wealthy LA neighborhoods between Mulholland Drive to the north and Sunset Boulevard to the south were part of the evacuation zone.
- Flames menacing art -
The Getty arts institution -- home to masterpieces including works by Edouard Manet -- was closed until at least Thursday.
Museum authorities tweeted that "air filtration systems are protecting the galleries from smoke."
The prestigious University of California at Los Angeles (UCLA) is near the same area and also ended up evacuating, after students began the day wearing masks.
Dozens of schools were closed, as was Santa Monica College.
Just north in Ventura County the "Thomas" blaze continued out of control, after erupting in the hills of oak and scrub north of Santa Paula, powered by strong seasonal guests known as Santa Ana winds.
- State of emergency -
At least 4,000 firefighters were deployed across the entire fire zone, including on the scene of the "Rye" blaze -- which had grown to 7,000 acres in the Santa Clarita area -- as well as the "Creek" fire north of downtown Los Angeles that had grown to more than 11,000 acres.
California Governor Jerry Brown declared a state of emergency over the area on Tuesday.
The Federal Emergency Management Agency (FEMA) said it had released funds for relief services.
US President Donald Trump tweeted a message of "thoughts and prayers" to California as it nears the end of its deadliest year ever for wildfires.