Firefighters battle heat and flames as a mansion burns during a wildfire in Santa Barbara, Calif., on Thursday night. (Mark J. Terrill/Associated Press)

California Gov. Arnold Schwarzenegger declared a state of emergency for Santa Barbara County on Friday, as firefighters and aircraft battled a raging wildfire that has destroyed about 100 multimillion-dollar homes and burned across over 800 hectares of land.

More than 13 injuries, including smoke inhalation and burns, have been reported since the fire started around 6 p.m. local time Thursday. Two people suffered serious burns in the blaze.

The fire was moving toward the city of Santa Barbara on Friday morning after tearing through the upscale coastal community of Montecito the night before, destroying about 100 mansions, officials said.

Fire officials said they feared the return of afternoon winds, known as "sundowners," which fuelled the blaze the day before and turned rolling hills around the celebrity enclave, about 150 kilometres northwest of Los Angeles, into a glowing inferno.

"We're going to have a very, very tough day today for firefighting and when the winds kick up this afternoon, we're going to have an incredibly challenging situation," said Santa Barbara County fire Chief Ron Prince.

'I've never seen that reddish, hellish glow that close. I was waiting for Dante and Virgil to show up.'—Ed Nahan, local resident

"Control of this fire is not even in sight."

More than 500 firefighters were trying to curb the flames before they reached the dense neighbourhoods of the city.

The aggressive attacks from the air include nine water-dropping helicopters and 10 air tankers, said Terri Nisich, spokeswoman for the San Barbara County executive office.

Fire crews, including 125 engines, from neighbouring counties are also helping battle the fire, Nisich said.

Many homes had been saved thanks to the "super-heroic efforts" of firefighters at the scene, said Prince.

More than 100 mansions were destroyed after a wildfire burned through the upscale community of Montecito, Calif., Thursday night. (Mark J. Terrill/Associated Press) Firefighter Matt Linsey uses a chainsaw to remove branches from a tree while trying to save a house in Santa Barbara. (Michael Moriatis/Associated Press) A house burns as flames rip through Montecito on Thursday night. (Dan Steinberg/Associated Press)

The fire has since been fanned by 110 km/h winds, which were expected to decrease to about 40 km/h on Friday.

The high winds and thick smoke on Thursday night forced helicopters battling the flames to land, Nisich said.

"We're expecting conditions to improve for firefighters on the lines, but it will still be warm and dry through tomorrow," said Jamie Meier, a meteorologist with the National Weather Service.

The flames were within 10 kilometres of Santa Barbara by Friday morning and about 20 homes within Santa Barbara city limits have already been destroyed, according to officials.

The growing blaze has already sent about 200 people to an evacuation centre at a high school in nearby Goleta.

Area resident Ed Nahan, who was able to gather his insurance documents and two dogs before fleeing his home with his wife, said he's worried about his house.

"I don't think we are going to have the house when we go back," Naha said. "We are used to seeing smoke because we do have fires up here, but I've never seen that reddish, hellish glow that close. I was waiting for Dante and Virgil to show up."

Southern California is experiencing unseasonably hot weather, drought conditions and forecasts of strong Santa Ana winds blowing in from the desert over the weekend, putting the region on high forest fire alert.

Homeowners in the area include actors John Cleese, Christopher Lloyd and Rob Lowe, as well as talk-show host Oprah Winfrey and Google Inc. chief executive Eric Schmidt. Officials are not releasing the names of owners of the destroyed properties.

'Like Armageddon': actor Lowe

In an interview with a local TV station, Lowe said he and his family fled their home with just minutes to spare and received no warning from authorities.

He said he was watching football with his son when his wife called him on the phone to alert him of the danger.

Lowe described how the entire mountain around his Montecito home was on fire and flames were shooting 60 metres in the air.

The actor said his home was ultimately spared, but as they left, the wind was blowing at 110 kilometres an hour and "it was just like Armageddon."

Lloyd, best know for his portrayal of eccentric scientist Dr. Emmett Brown in the Back to The Future film trilogy, was not so lucky.

The caretaker for Lloyd's $11 million US estate "fled for his life" in the firestorm Thursday night, the Los Angeles Times' real estate columnist reported, quoting the actor's property manager at Sotheby's International Realty. She said the home was "at least partially burned, if not totally."

A residence building and several classrooms at the private Westmont College were also destroyed by the fire, forcing some 1,000 students to take shelter in a fireproof gymnasium, said officials.

"I saw flames about 100 feet high in the air shooting up with the wind just howling," said college spokesman Scott Craig.

"Now when the wind howls and you've got palm trees and eucalyptus trees that are literally exploding with their hot oil, you've got these big, red hot embers that are flying through the sky and are catching anything on fire."

Montecito last suffered a major fire in 1977, when more than 200 homes burned. A fire in 1964 burned about 27,000 hectares and damaged 150 houses and buildings.

Thick plumes of smoke were in the sky over the area through much of the day on Friday.

About 5,400 residents were evacuated from the area because of the flames and officials were reporting on Friday that about 20,000 people had lost power because of the fire. Officials said Friday that more people were expected to be evacuated from the area.

With files from the Associated Press and Reuters