Firefighters hoped to begin reducing their air operations Tuesday as they made progress against the group of wildfires that had blackened some 131 square miles east of Los Angeles and destroyed nearly 60 homes.

They also kept watch on thunderstorms that could bring either helpful rain or dangerous lightning, wind, mudslides and floods.

Firefighters using hand tools on steep terrain were warned to be careful not to lose their footing on muddy hillsides.

Click here to visit FOXNews.com's Natural Disaster Center

"It makes an already treacherous situation more so," Craig Vanderzwaag, a fire information officer, said early Tuesday.

There was a 70 percent chance of rain Tuesday, after light rain in some areas on Monday, the National Weather Service said.

The edge of the fires was only a few miles from the tiny town of Rainbow and just eight miles from Big Bear, a community of thousands. However, no evacuations were called, and firefighters were making progress on corralling the blaze, officials said.

"The greatest thing that we got is cloud cover," said Rich Phelps, a U.S. Forest Service spokesman.

The largest fire in the cluster, about 61,700 acres, was 85 percent contained and crews hoped to surround it by Tuesday evening. That fire destroyed 58 houses and mobile homes, dozens of outbuildings and scores of vehicles in the 96-square-mile area. One death was believed to be related to the fire.

"We've pretty much stopped the forward spread," said Nick Rossman, a spokesman for the California Department of Forestry.

Fire officials were planning to scale back their air operation, Vanderzwaag said.

The second major part of the cluster, covering some 24,210 acres or about 38 square miles, was 49 percent contained. Full containment probably was three to five days away, said Tom Wadley of the U.S. Forest Service.

Fire officials estimated damage at nearly $12 million and firefighting costs at $21.5 million.

Elsewhere, officials in south-central Montana were optimistic that crews were gaining the upper hand in fighting three blazes estimated at 121,500 acres, or about 190 square miles. They were 60 percent contained, said Dixie Dies, a Forest Service fire information officer.

A wildfire in northern Minnesota had exploded to more than 23 square miles in three days, feeding on millions of trees blown down by a storm in 1999.

All those dead trees made it too dangerous to send ground crews in, said Marty Christensen, a U.S. Forest Service official.

"Because the fuel we have is so intense, it's beyond control with hand crews, mechanized crews or aircraft," Christensen said. "So really, the fire is doing what it wants to do."

Southeast of Reno, Nev., a 1,000-acre fire near the border with California had forced the evacuation of campers and some homes near the ranching community of Wellington.

In west-central Utah, Interstate 15 was reopened about midnight after being closed several hours because of a brush fire that also prompted evacuations in and near the town of Cove Fort. The fire had blackened more than 12 square miles, authorities reported.

Wyoming firefighters expected full containment Tuesday on a group of fires that had burned more than 14,900 acres southwest of Devils Tower National Monument.