Idyllwild fire mostly contained. Now mudslide threatens California homes.

A Southern California wildfire that destroyed seven homes and threatened the mountain town of Idyllwild was sluggish after a thunderstorm drenched the timberland, and more storms doused the remaining flames on Monday.

The 43-square-mile fire above Palm Springs was 85 percent contained. It didn't move overnight and crews concentrated Monday on surrounding it on ridges thousands of feet up in the San Jacinto Mountains, U.S. Forest Service spokesman Lee Beyer said.

"It's pretty much in the smoldering category right now," Beyer said. "There's no moving fire."

The rain was beneficial for firefighters, but powerful downpours also raise the potential for flooding and mudslides in recently burned areas, prompting authorities to issue a voluntary evacuation warning for about 20 homes several miles southeast of Idyllwild.

With rain in the area "it has the potential to be more serious," Beyer said. "If it's raining hard now, it's going to be bringing the mud down in a very short time."

Thousands of evacuees were allowed back home Sunday as a thunderstorm dumped up to 2 inches of rain on portions of the week-old fire.

About 1,900 firefighters were assigned, down from some 3,300 at the fire's height, and more will be removed as the fight winds down, Beyer said.

More storms are expected in the next couple of days - and that could prove a mixed blessing, he said.

"Light rains are good, heavy rains create mud flows," Beyer said. "Thunderstorms obviously have lightning with them. That's always a safety concern when you have people up on those exposed ridges."

Crews also must watch out for possible falling burnt trees, he said.

Some 6,000 people fled the idyllic little towns that dot the San Jacinto Mountains between Palm Springs and Hemet after the fire broke out July 15 and quickly raged across the heavily wooded area. Twenty-three structures, including the seven homes, were destroyed. There were no reports of injuries.

Authorities have said the fire was human-caused but wouldn't say whether it was accidental or intentional.

Full containment is expected on Wednesday.