Firefighting aircraft have dropped water and fire retardant to stem the eastward spread of wildfires in Los Angeles as on-the-ground efforts intensified amid warnings of powerful winds.

Over the past 24 hours, the Palisades Fire spread over an additional 1,000 acres, officials reported, and consumed more homes.

Earlier on Saturday,  fire official Todd Hopkins told reporters that while 11 per cent of the Palisades fire was now contained, it has burned over 8,900 hectares.

Hopkins said the Palisades Fire had spread into the Mandeville Canyon neighbourhood and threatened to jump into Brentwood, an upscale neighbourhood, and the San Fernando Valley.

The National Weather Service warned of worsening Santa Ana winds that it predicted would pick up Saturday night into Sunday morning in Los Angeles and Ventura counties, and again on late Monday through to Tuesday morning, bringing sustained winds up to nearly 50 km/h and gusts up to 112 km/h.

“We’re in a continued period of critical fire weather through Wednesday,” said meteorologist Rose Schoenfeld. Conditions were expected to moderate by Thursday.

Evacuation orders throughout the Los Angeles area now cover 153,000 residents with another 166,000 warned they may have to evacuate, said Los Angeles County Sheriff Robert Luna.

Luna added his office had dispatched 40 search and rescue  workers to work jointly with other agencies, including the use of cadaver dogs to search for remains of victims and to help reunite families that have been separated.

As state and local officials grappled with the worst cluster of fires in Los Angeles history, President Joe Biden spoke by phone with some of them to get an update on their efforts and was also briefed by his senior aides on federal resources that were being dispatched.

Biden’s major disaster declaration unlocked federal assistance for those affected by the wildfires.

Federal Emergency Management Agency officials were at the Pasadena Convention Centre helping residents navigate aid applications.

Spokesman Michael Hart said support can range from funding to help with home repairs to money to replace lost food or medication. The assistance can be provided within a matter of days, he said.

Los Angeles Board of Supervisors Chair Kathryn Barger told reporters that she invited President-elect Donald Trump to visit the county to get a first-hand look at the destruction.

Six simultaneous blazes that have ripped across Los Angeles County neighbourhoods since Tuesday have killed at least 13 people and damaged or destroyed 12,000 structures. At least 13 people are estimated to be missing so far.

The toll is expected to mount when firefighters are able to conduct house-to-house searches.

The fierce Santa Ana winds that fanned the infernos eased on Friday night. But the Palisades Fire on the city’s western edge was heading in a new direction as winds came off the Pacific Ocean.

The fires have razed whole neighbourhoods to the ground, leaving just the smouldering ruins of what had been people’s homes and possessions.

On Friday morning, hundreds of people streamed into a parking lot near the Rose Bowl stadium in Pasadena for donated clothing, nappies and bottled water.

Beyond those who lost their homes, tens of thousands remained without power, and millions of people were exposed to poorer air quality, as the fires lofted traces of metals, plastics and other synthetic materials.

The two biggest fires, in Palisades and Eaton combined,  had consumed over 14,500 hectares, 2 and a half times the land area of Manhattan.

Seven neighbouring states, the federal government and Canada and Mexico have rushed aid and firefighters to California, bolstering aerial teams and crews on the ground attacking fire lines with hand tools and hoses.

Private forecaster AccuWeather estimated the damage and economic loss at $135 billion to $150 billion, portending an arduous recovery and soaring homeowners’ insurance costs.

Source: AAP