YUCCA VALLEY -- Crews battling wildfires that had destroyed 58 homes and blackened more than 110 square miles faced a threat of thunderstorms Sunday that could produce lightning capable of starting new blazes -- or heavy rain that would flood the newly denuded land.

"We're definitely concerned," said Karen Guillemin, spokeswoman for the California Department of Forestry.

The National Weather Service said there was about a 30 percent chance of storms in the region, roughly 100 miles east of Los Angeles.

Nearly 4,000 firefighters were struggling to surround the combined fires before they could endanger mountain resort towns where thousands live.

The body of a man who had been missing since one of the fires rushed through historic Pioneertown last week was found Saturday, said Cindy Beavers of the San Bernardino County Sheriff's Department.

The cause of death remained under investigation, but the body of Gerald Guthrie, 57, was found in a charred area less than a half-mile from his home, which escaped the flames that destroyed desert scrub and Joshua trees. A family member last heard from Guthrie when he called and said that the fire was close and that he was preparing to evacuate, authorities said.

Before Sunday's threat of unsettled weather, higher humidity and slightly lower temperatures helped crews make some progress on the fires, which covered areas totaling about 75,000 acres.

One, a blaze of 62,000 acres, or about 97 square miles, was 60 percent contained Sunday, a week after it was started by lightning.

A mandatory evacuation remained in effect for one small canyon but had been lifted in several other areas. That blaze had destroyed 58 desert houses and many outbuildings. Fire officials estimated damage at more than $8.4 million and firefighting costs at $10.3 million.

An adjacent group of fires had grown to more than 15,000 acres since merging with the larger fire and was 10 percent contained, officials said. There were no evacuations.

The fires had burned into the San Bernardino National Forest but were not considered immediate threats to communities at higher elevations in the Big Bear Lake region.

Gov. Arnold Schwarzenegger toured the area by helicopter on Saturday.

"It is a huge fire. It is really extraordinary how quickly it has spread out," Schwarzenegger said later.

Elsewhere in Southern California, a 500-acre blaze at Redlands was fully contained Sunday after destroying one building. It broke out Friday night and initially threatened 100 homes.

In San Diego County, a 260-acre wildfire about 10 miles east of Julian also was fully contained, said California Department of Forestry spokeswoman Roxanne Provaznik.

Firefighters in southern Montana were battling major fires that charred about 185,000 acres, mostly east of Billings. About 125 homes were potentially threatened, officials said.

In Wyoming, a wind shift helped firefighters keep a wildfire from advancing toward Devils Tower National Monument. Four fires about 5 miles southwest of Devils Tower have burned about 13,700 acres -- about 21 square miles -- of mostly brush and ponderosa pine. About 10 percent of the fires were contained.

On the Net:

California Forestry Department: http://www.fire.ca.gov/php/

National Interagency Fire Center http://www.nifc.gov