RED BLUFF, Calif. (AP) _ Fire crews in California reduced the threat today to 1,600 homes and gained the upper hand on wildfires that have burned 400 square miles, closed Yosemite National Park and killed one firefighter.

Crews also reined in most of Idaho's forest fires, and the last two fires in Utah were subdued. More than 40 blazes burned in Washington's Wenatchee National Forest. Small fires burned in Wyoming, Montana and Arizona.

But lightning and high wind during the night heated up two eastern Oregon forest fire complexes totaling an estimated 22,000 acres and spread them to the north today as 3,700 firefighters worked to halt the advancing flames.

Unseasonably hot, dry weather threatened to make 99 fires in Alaska more active, the National Fire Information Center said.

In northern California, a fast-moving fire that came within 4 miles of the town of Manton and had threatened almost 1,600 homes was at least 60 percent contained Tuesday, said Forestry Department spokesman Dwayne Collier.

''The weather was certainly in our favor today and we have good resources out there,'' Collier said. ''It's been a good day all the way around.''

At least 31 fires continued to burn in Yosemite National Park, but authorities predicted they would be contained by Friday. The fires have burned more than 22,000 acres there and have closed the park since last week.

Burning trees alongside the park's highways still pose a danger, said Janet Buzzini of the U.S. Forest Service.

''They're still toppling onto roads,'' she said. ''We cannot open the park until we get those closest to the roads down.''

Rolling rocks also pose a threat, Buzzini said. ''There's really nothing to hold some of these in place, plus there's a lot of crews and equipment on the roads,'' she said. ''It's really not safe yet.''

Hazardous materials workers went to a section of the park where 66 homes were destroyed to check for PCBs and asbestos before allowing residents to return, said Forestry Department spokeswoman Candy Johnson.

Kenneth Earl Enslow, 20, died Tuesday after being struck by a tree limb in Mendocino National Forest on Monday. Enslow was the first person killed in California in the blazes that began Aug. 3 and have cost $15 million to fight.

About 100 Army soldiers began arriving Tuesday from Fort Carson, Colo., to help mop up a fire that has scorched 18,744 acres in Shasta County, officials said. Some 1,200 troops took a crash course in firefighting over the weekend.

''The guys coming out here, they view it as a very important mission,'' said Maj. John Mims. ''They're ground-pounders, young kids, physically fit and aggressive.''

The California fires have been caused mostly by lightning, with more than 31,000 strikes counted since Aug. 3, said Forestry Department spokesman Norm Benson. The fires have burned 260,000 acres, or about 400 square miles.

In Idaho, crews were to protect isolated buildings today from creeping backcountry blazes. Firefighters sprayed fire-resistant foam on buildings in the Frank Church River of No Return Wilderness Area.

The two big Oregon fire complexes were burning about four miles apart 35 miles north of Burns. No structures were threatened. The Snowshoe fires were 40 percent contained and the Sheep Mountain complex was 55 percent contained, officials said. Firefighters don't expect either set of fires to be contained until Monday.