San Diego ? Ash fell on the beach like snow and drivers turned on their headlights in the smoky daytime streets Monday as wildfires that have reduced entire neighborhoods to moonscapes skipped through the hills of Southern California and threatened 30,000 more homes.

California’s deadliest outbreak of fires in more than a decade has destroyed at least 1,134 homes, killed at least 15 people and consumed more than 483,000 acres stretching from the Mexican border to the suburbs northeast of Los Angeles.

“This will be the most expensive fire in California history, both in loss of property and the cost of fighting it,” Dallas Jones, director of the state Office of Emergency Services, said Monday.

Several people suffered burns and smoke inhalation, including eight hospitalized at the University of California, San Diego, Medical Center. Two had burns over more than 55 percent of their bodies, spokeswoman Eileen Callahan said.

Managers of California’s power grid estimated that 70,000 to 85,000 Southern California customers were without electricity because fires had damaged transmission lines.

The dry, hot Santa Ana winds that have fanned the flames began to ease Monday, raising hopes that overwhelmed firefighters could make progress with the help of reinforcements on their way from other Western states. But the danger was still high.

President Bush designated the fire-stricken region a major disaster area, opening the door to grants, loans and other aid to residents and businesses in Los Angeles, San Bernardino, San Diego and Ventura counties.

“This is a devastating fire and it’s a dangerous fire. And we’re prepared to help in any way we can,” Bush said.

Gov. Gray Davis moved to activate the National Guard and summon help from neighboring states. He predicted the cost of the fires would be in the billions.

A strike team from Orange County Fire Authority stands its ground against a wall of flames to save a vehicle and home as fire approaches in Ramona, Calif. While wildfires receded somewhat on Monday, an emergency official still predicted damage would be the worst in state history.

He toured the fire area in San Bernardino and saw “just homes reduced to rubble, charred belongings still sending off smoke.”

He was followed later by Gov.-elect Arnold Schwarzenegger, who had a fire briefing in Ventura County and praised work by firefighters.

He thanked Bush for swiftly declaring an emergency and said he would go to Washington today to meet with federal officials “to make sure that the federal money will come through.”

“I want to thank them for their hard work. The … firefighters are the true heroes. They’re risking their lives in order to save people’s lives,” Schwarzenegger said.

A U.S. Forest Service DC-4 drops fire retardant in an attempt to protect the luxury homes in Los Angeles County.