Firefighters battling 15 fires across Southern California got a break from slowing winds yesterday, but major blazes burned unchecked for a fourth day after forcing the largest evacuation in California's modern history.

Some 1,300 homes have been lost in San Diego county, the most critical area, and an official estimated damages would exceed $1 billion.

"Based on initial estimates, just the homes damaged will be over $1 billion,"Ron Lane, San Diego County emergency services director, told a news conference.

Two big fires merged in the county and covered more than 80,000 hectares, half of the total burned area in California.

More than 500,000 people have been forced to leave their homes in California. "We have several tremendous fires still going on," San Diego Mayor Jerry Sanders said yesterday.

The Los Angeles County area showed major progress against blazes, and, although mountain fires continued to burn, firefighters expressed hope that yesterday would be the turning point.

"The wind today, we hope, is not going to be nearly as drastic as it was yesterday," firefighter Jim Christian told local television.

Despite the wide-scale devastation, loss of life has been minimal. One person was killed in San Diego on Sunday, while four other deaths were reported among the evacuees.

Around 18 firefighters have been injured out of the 10,000 on the fire lines.