California wildfires that have destroyed 1,300 homes and forced the evacuation of 500,000 people raged into a fifth day on Thursday but firefighters seized on a break in the weather to largely halt the march of destruction.

Some 15 fires still blazed across the southern part of the state, lighting up the night sky, but officials said cooler temperatures and weaker winds allowed them to win a measure of control for the first time and that the worst was behind them.

President George W. Bush, who declared California's wildfires a "major disaster," triggering extra federal help, was due to survey the damage with Gov. Arnold Schwarzenegger on Thursday and check on the government's response.

Already the Federal Emergency Management Agency, criticized along with Bush for being slow to respond to Hurricane Katrina in 2005, had 1,000 people on the ground in badly scorched San Diego County.

Though fire officials were relieved that the hot, dry Santa Ana winds driving the flames had weakened, they conceded that offshore breezes replacing them presented a danger. Even those milder winds could trigger dangerous runs by some of the fires, which were being fought by some 9,000 weary men and women.

The wildfires, which broke out over the weekend after the Santa Ana winds began to blow, have blackened nearly 800 square miles, claimed six lives and injured dozens of people, many of them firefighters.

'DESTINED TO BURN'

San Diego County has suffered losses in excess of $1 billion, and three of the largest fires still burned out of control there.

"It is just like a chess game as to which area is the highest priority. We are the highest priority now," said Jeff Terpstra, a fire chief at the nearly 200,000-acre (80,940- hectare) Witch fire. "Some of this area hasn't burned for 25 to 45 years. It is destined to burn."

But after the largest evacuation in California's modern history, some residents were allowed to go home and find out if their houses still stood.

One of the most desperate fights was in Orange County, south of Los Angeles, where the 20,000-acre (8,094-hectare) Santiago fire for a time menaced homes in a gated community.

Authorities said federal agents from the FBI and Bureau of Alcohol, Tobacco and Firearms joined local authorities in investigating the Santiago fire as arson.

"Those are crime scenes," said Jim Amormino, spokesman for the Orange County Sheriff's Department, adding that a $70,000 reward was posted for information leading to the arrest and conviction of those responsible.

Los Angeles County has reported the most progress, canceling wind warnings for the first time since the weekend.

San Diego County officials said that even when the fires were extinguished they would face a major cleanup and huge costs. Based on initial estimates, just the homes damaged will be worth more than over $1 billion, said Ron Lane, San Diego County's emergency services director.

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