Weather improves conditions in Calif.

LAKE ARROWHEAD, Calif. -- Firefighters battled stubborn wildfires across Southern California on Saturday, but scattered showers brought a welcome improvement in conditions.

Tropical moisture flowing from the south replaced the hot, dry Santa Ana winds that roared in a week earlier and spread fires over more than a half-million acres, destroying more than 2,300 structures, including 1,700 homes.

The number of deaths directly attributed to the fires officially rose to seven. Officials confirmed that the flames killed four suspected illegal immigrants whose charred bodies were found near the U.S.-Mexico border Thursday, said Jose Alvarez, a public information officer for San Diego County emergency services. Identification of the victims was continuing.

Although more than a dozen blazes were surrounded, containment of nine other blazes ranged from 97 percent to just 25 percent. More than 21,000 structures were considered threatened, and more than 15,000 firefighters were on the lines, the state Office of Emergency Services said.

"It's very overcast right now, no wind. Low humidity, about 30 percent. They're talking about rain," said Audrey Hagen, a spokeswoman for the California Department of Forestry and Fire Protection in San Diego.

Active fires burned in the Lake Arrowhead resort region of the towering San Bernardino Mountains 100 miles east of Los Angeles and in rugged wilderness above isolated canyon communities of Orange County, southeast of Los Angeles. A big blaze 60 miles northeast of San Diego stopped its advance toward the mountain town of Julian.

Gov. Arnold Schwarzenegger told a news conference that he would work to improve problems in the state's deployment of firefighting aircraft when major wildfires erupt. Nearly two dozen military helicopters stayed grounded for days after several wildfires broke out because state personnel who must be on board were not immediately available.

Two of the California National Guard's C-130 cargo planes also couldn't help because they've yet to be outfitted with tanks needed to carry thousands of gallons of fire retardant, though that was promised four years ago.

"There are things that we could improve on, and I think this is what we are going to do because a disaster like this ... in the end is a good vehicle, a motivator for everyone to come together," Schwarzenegger said. "I remember after Katrina, as sad as it is, but it takes sometimes a disaster like this to really wake everyone up and affect things."

In Southern California fire areas, about 4,400 people remained in 28 shelter sites, but others waited out the fires in makeshift encampments.