A dramatic new wildfire has erupted in Los Angeles as firefighters battle three other destructive blazes across southern California.

Flames exploded before dawn on the steep slopes of Sepulveda Pass, which carries the busy Interstate 405 through the Santa Monica Mountains, where ridge tops are covered with expensive homes.

Firefighters were providing structure protection as helicopters flying in darkness made water drops on the flames on the east side of the pass.

Hundreds of homes burned in the area during the famous Bel Air Fire of 1961.

The Getty Centre art complex, on the west side of the pass, employs extensive fire protection methods.

Elsewhere, use of firefighting aircraft has been constrained by the same winds that have spread the fires.

The water-dropping planes and helicopters essential to taming and containing wildfires have been mostly grounded because it is too dangerous to fly them in the strong wind.

Tuesday saw gusts of more than 50mph.

A truck drives along the 101 Freeway in Ventura through flames (AP)
A truck drives along the 101 Freeway in Ventura through flames (AP)

Commanders hoped to have them back in the air on Wednesday, but all indications were that the winds will be whipping then too, fanning the flames that spurred evacuation orders for nearly 200,000 people, destroyed nearly 200 homes and remained mostly out of control.

“The prospects for containment are not good,” Ventura County fire chief Mark Lorenzen said. “Really, Mother Nature’s going to decide when we have the ability to put it out.”

Southern California’s Santa Ana winds have long contributed to some of the region’s most disastrous wildfires.

They blow from the inland towards the Pacific Ocean, speeding up as they squeeze through mountain passes and canyons.

The largest and most destructive of the fires, an 85-square mile wildfire in Ventura County north-west of Los Angeles, had nearly reached the Pacific on Tuesday night after starting 30 miles inland a day earlier.

The wildfire jumped the major artery US Highway 101 to a rocky beach north-west of Ventura, bringing new evacuations, though officials said the sparse population and lack of vegetation in the area meant it was not overly dangerous.

The fire had destroyed at least 150 structures, but incident commander Todd Derum said he suspects hundreds more homes have already been lost, though firefighters have been unable to assess them.

While the blazes brought echoes of the firestorm in northern California that killed 44 people two months ago, no deaths and only a handful of injuries had been reported. In the foothills of northern Los Angeles, 30 structures burned.

Mayor Eric Garcetti said the gusty winds expected to last most of the week had created a dangerous situation and he urged 150,000 people under mandatory evacuation orders to leave their homes before it is too late.

“We have lost structures, we have not lost lives,” he said. “Do not wait. Leave your homes.”

Fires are not typical in southern California this time of year but can break out when dry vegetation and too little rain combine with the Santa Ana winds.