The Palisades Fire between Santa Monica and Malibu on the city's western flank and the Eaton Fire in the east near Pasadena already rank as the most destructive in Los Angeles history, consuming nearly 12,500 hectares and turning entire neighbourhoods to ash.
At least five people have been killed, thousands of homes and businesses have been incinerated and nearly 180,000 people have been ordered to evacuate their homes, with another 200,000 under evacuation warnings, officials said.
The death toll is likely to rise, Los Angeles Sheriff Robert Luna told a press conference on Thursday, adding that the Eaton Fire alone had damaged or destroyed 4000 to 5000 structures. Officials said the Palisades Fire destroyed an estimated 1000 more.
Emergency authorities say the Eaton fire remains uncontained but its growth has stopped. (AP PHOTO)
Some Pacific Palisades residents ventured back to areas the fire had already swept through, where brick chimneys were left looming over charred waste and burnt-out vehicles. The remnants of a tattered and scorched American flag flapped from a pole.
Thousands of Angelenos fleeing the flames sought refuge in temporary shelters.
The Eaton Fire's growth has been significantly stopped, Los Angeles County Fire Chief Anthony Marrone said, though it remains zero per cent contained. While still strong, winds have diminished since the 160km/h gusts seen earlier in the week, permitting crucial aerial support for crews on the ground.
But officials warned that the wind was forecast was due to intensify again in the evening, with gusts of up to 100km/h. The National Weather Service extended its red flag warning for the area until 6pm on Friday, meaning the dry, strong Santa Ana winds would continue to pose an increased fire risk until then.
The Los Angeles City Fire Department said residents should be prepared to evacuate if ordered.
Pacific Palisades homes of some celebrities have been destroyed amid wildfires in California. (AP PHOTO)
In Pacific Palisades, an upscale and picturesque enclave where many celebrities reside, once-palatial homes stood in ruins, while downed power lines and abandoned cars littered the roadways. The smell of heavy smoke filled the air, and residents wearing masks rode bicycles, hoping to catch a glimpse of their damaged houses.
Aerial video showed block after block of levelled homes, while satellite images showed thick plumes of smoke from the fires being blown in a southwesterly direction out over the Pacific Ocean.
The two biggest conflagrations - the Palisades and Eaton fires - formed a pincer around the city so enormous that it was visible from space.
Firefighting crews managed to beat back a third blaze, known as the Sunset Fire, which had forced mandatory evacuations in Hollywood and Hollywood Hills - including famous show-business locations such as the TCL Chinese Theatre and the Hollywood Walk of Fame - late on Wednesday.
The fire was fully contained, Los Angeles Mayor Karen Bass said on social media around midday on Thursday. No buildings were lost in the area, a city fire department spokeswoman said, and the evacuation order was lifted.
It was one of at least five separate wildfires burning in Los Angeles County on Thursday as powerful winds spread flames across parched ground that has seen no rain for months. Bass described it as a "perfect storm" of dangerous conditions.
President Joe Biden, who declared a major disaster in California, met with top administration officials in the afternoon to discuss the federal response, the White House said.
A resident of a senior centre is evacuated as the Eaton Fire approaches in Altadena, California. (AP PHOTO)
The homes of movie stars and celebrities were among those consumed by flames, which tore through some of the world's most lavish real estate.
Chef Jose Andres, the Spaniard known for providing free food to disaster victims around the world, set up a food truck near the Palisades Fire on Pacific Coast Highway.
"Everybody needs support and love in these moments, wealthy or not, poor or not. It's he right thing to do. So you try to make sure nobody is left behind," he said.
Actress Jamie Lee Curtis on Thursday said her family would donate $US1 million ($A1.6 million) to relief efforts.
Firefighters from six other US states were being rushed to California, while an additional 250 engine companies with 1000 personnel were being moved from Northern to Southern California.
