The weather change strengthened a 32,000-acre fire in the Helena National Forest about 60 miles east of Missoula. Flames threw embers up to a half-mile away toward homes that had been evacuated.
Fire managers turned more resources toward the blaze, which officials expected to reach the Continental Divide, where they were counting on terrain and water drops to stop it.
``We have all sorts of engines up there working on that right now,'' Bob Brousseau, fire information officer, said Tuesday afternoon.
Crews aided by cooler, damper weather over the past week had contained about a dozen blazes in the Northern Rockies region.
With the weather change, fire managers feared the wind could blow some of Montana's roughly three dozen blazes out of control again.
``The expectation is that the winds will pick up later tonight, so things should remain fairly quiet until then,'' Linda Slater, fire information officer with the Northern Rockies Coordination Group, said Tuesday afternoon.
A 7,000-acre fire about nine miles west of Missoula had burned three homes and was 75 percent contained Tuesday, while a 31,000-acre fire farther west was just 22 percent contained and still threatens about 200 homes, fire managers said.
Fires have blackened more than 400,000 acres in Montana this summer.
In Wyoming, firefighters said they were making progress toward getting Yellowstone National Park's east entrance reopened Thursday morning.
The east entrance, one of five into Yellowstone, had been closed for more than a week because of fires. It was reopened for limited traffic during the weekend but closed again Monday, sending travelers heading to the park from Cody, Wyo., on a 29-mile detour.
Two wildfires burning in central Oregon continued to keep away about a thousand residents from the resort town of Sisters. The fires had burned 39,000 acres and threatened to merge, standing just four miles apart Tuesday. Officials had hoped to allow limited returns beginning Wednesday but with new spot fires reported Monday night, the return was postponed.
Large fires also were active Tuesday in Alaska, Arizona, California, Colorado, Idaho and Washington, the National Interagency Fire Center reported. So far this year, wildfires have blackened 2.5 million acres, compared to 6.1 million at the same time last year, the center said.
