Millions face new wildfire warnings in southern California as winds rise

Millions of people across Southern California have faced new wildfire warnings, and tens of thousands saw their power shut off as strong winds blew across the parched landscape around Los Angeles, where two massive blazes have been burning for a week.

Santa Ana winds that began gusting over the mountains before sunrise were forecast to continue with enough force to carry fire-sparking embers for kilometres and stoke new outbreaks across a region where at least 24 people have already been killed.

"Life-threatening and destructive and widespread winds are already here," LA city Fire Chief Kristin Crowley told a news conference on Tuesday.

Much of Southern California was under an elevated fire risk, with crews on high alert across a 482 km stretch from San Diego to far north of Los Angeles.

Facing the greatest risk were inland areas north of LA, including densely populated Thousand Oaks, Northridge and Simi Valley, home to more than 300,000 people, forecasters said.

Nearly 90,000 households lost electricity as utilities shut off power to prevent their lines from sparking new blazes.

Unusual warning

Tuesday's forecast included a rare warning: The winds, combined with severely dry conditions, have created a "particularly dangerous situation," meaning that any new fire could explode in size.

Gusts will pick up strength in the evening and into Wednesday before decreasing, and red-flag warnings now up from Central California to the Mexican border will remain through most of Wednesday, weather service meteorologist Ariel Cohen said.

Planes doused homes and hillsides with bright pink fire-retardant chemicals, while crews and fire engines deployed to particularly vulnerable spots with dry brush.

Los Angeles Mayor Karen Bass and other officials who were criticised over their initial response expressed confidence that the region is ready to face the new threat.

The mayor said she was able to fly over the disaster areas, which she described as resembling the aftermath of a "dry hurricane."

Winds this time were not expected to reach the same fierce speeds seen last week but could ground firefighting aircraft, LA County Fire Chief Anthony Marrone said.

He warned that if winds reach 112 kph, "it's going to be very difficult to contain that fire."

He urged people experiencing homelessness to avoid starting fires to keep warm and said they should seek shelter.

Wildfires on rise across LA

With almost no rain in more than eight months, the brush-filled region has had more than a dozen wildfires this year, mostly in the greater Los Angeles area.

Firefighters have been jumping on small fires that pop up. One such blaze, in a dry riverbed near Oxnard Monday night, was quickly smothered. "We've got helicopters ready to go, to drop water on any new fires," said Andrew Dowd, a spokesperson for the Ventura County Fire Department.

The four biggest fires around the nation's second-biggest city have scorched more than 163 square kilometres, roughly three times the size of Manhattan.

Of these, the Eaton Fire near Pasadena was roughly one-third contained, while the largest blaze in Pacific Palisades on the coast was far less contained.

The death toll is likely to rise, Los Angeles County Sheriff Robert Luna said. At least two dozen people remained missing, he said Tuesday. Some people earlier reported as missing have been found.