Los Angeles - The first serious wildfire of the season has destroyed at least 12 houses in the posh Southern California city of Santa Barbara, the Los Angeles Times reported.

Coming more than a month before summer officially begins, Tuesday's fire underscored the growing threat facing the US state as climate change makes wildfires hotter, bigger and more frequent.

The fire was fed by winds of up to 80 kilometres an hour, which sent glowing clouds of embers and thick blankets of smoke across the Pacific coast mountainsides and toward the densely populated town centre and the Pacific Ocean.

The smoke was so thick that firefighters refrained from estimating the area that had been scorched. Helicopters and aircraft also were temporarily grounded.

Two firefighters were trapped in a house that caught fire and suffered serious burns, the Santa Barbara News-Press said.

"We are in a state of extreme emergency," David Sadecki, a spokesman for the Santa Barbara County Fire Department, was quoted as saying. "We're running very, very thin."

The fire came six months after a blaze in the same area burned more than 200 houses and prompted California Governor Arnold Schwarzenegger to declare a state of emergency.

Experts predicted that California would face a growing threat from wildfire because of climate change and because development has pushed homes further into wildlands.

Santa Barbara Mayor Pro Tem Dale Francisco told KABC-TV Channel 7 that firefighters were trying to make a stand but that "when these winds are blowing hard enough, nothing can stop it."