Hurricane-force winds have sent wildfires ripping through the mountains and foothills around Los Angeles.
Fireballs leapt from house to house, torching entire streets and destroying more than 1,000 buildings.
The scale and speed of the unfolding disaster has left an apocalyptic wake of destruction.
Photos show devastating scenes from the worst wildfires in the US city's history.
The largest blaze has consumed more than 6,000 hectares in Pacific Palisades, a picturesque neighbourhood between the beach towns of Santa Monica and Malibu.
Burned-out luxury cars are seen on upmarket streets, surrounded by homes of celebrities.
Another deadly fire has been tearing through the Eaton Canyon in the foothills of the San Gabriel mountains north of LA.
Kevin McGowan, director of emergency management for Los Angeles County, said the city was facing "a historic natural disaster".
Tens of thousands of people have been evacuated from their homes, many in harrowing conditions.
Strong winds have been hindering firefighting efforts, and water supplies were running low.
More than 1,000 firefighters are battling multiple blazes across the city.
"There are not enough firefighters in LA County to address four separate fires of this magnitude," Los Angeles County Fire Chief Anthony Marrone said.
The Pentagon said it would send 10 Navy helicopters to help fight the fires.
The fires struck at an especially vulnerable time for Southern California, which has yet to see significant rainfall since the start of the water year in October.
Then came the powerful Santa Ana winds, bringing dry desert air from the east toward the coastal mountains, fanning the flames of the wildfires while blowing over the hilltops and down through the canyons.
Scientists said the fires, erupting well outside of the traditional wildfire season, mark the latest in weather extremes that are likely to escalate further as global temperatures continue to climb in coming decades.
ABC/Wires
