Blazes fanned by high winds roared through two states on Saturday, charring some 38,000 acres and at least a half-dozen houses in Montana while destroying 14 structures and forcing scores of residents to flee their homes in Colorado.
Firefighters hoped for help from an arctic front bringing windchill readings of 15 degrees below zero to 40 degrees below zero.
"The temperatures are dropping significantly and the humidity is coming up," said Jane Weber of the Lewis and Clark National Forest in Montana.
In the meantime, there were no immediate threats to life or property, she said, adding, "The firefighters are concentrating on protecting buildings."
Earlier, the fire--which was fanned by gusts of up to 100 m.p.h.--swept between the towns of Stanford and Hobson in central Montana, Weber said.
Other fires burned hundreds of acres of prime grizzly bear habitat 200 miles to the northeast, 9,000 acres in northern Fergus County, and for a time threatened homes in the Great Falls area.
Snow proved to be a friend to the bears. Once it began to fall before daybreak, the fire in the grizzly habitat was "pretty well controlled," said Jim Greene of the Department of State Lands.
More than 200 firefighters battled the Colorado blaze, which began shortly after 2 a.m. in a home northwest of Boulder.
Authorities arrested a man for investigation of arson and reckless endangerment. The suspect, who was identified as 62-year-old Arnold Stein, is accused of setting his mattress on fire in his home, then pulling it outside.
The blaze spread as 60 m.p.h. winds fanned the flames and destroyed 6,000 acres, officials said.
No major injuries were reported, but some firefighters reportedly suffered minor burns and smoke inhalation.
The 14 destroyed structures included homes and garages.
About 40 displaced residents gathered at an emergency evacuation center set up by the Red Cross at a junior high school. The Red Cross was making arrangements for shelter for the residents Saturday night, and mental health counselors were working with some families.
"A lot of people are showing up, registering and then making their own arrangements to stay with friends and family," said Capt. Chuck Pringle of the Boulder County Sheriff's Department.
Residents said the fire woke them up, and many were still drowsy and confused.
"My wife smelled smoke. . . . We jumped out of the house. We saw the flames go by the house and it seemed OK," said resident Rich Larson.
He said he and his wife then noticed two hot spots on the roof, and thinking that the fire had gotten to their attic, they evacuated.
About 100 rural volunteer firefighters and a team from Malmstrom Air Force Base in Great Falls fought the fire in central Montana, Weber said. Another 280 firefighters were being sent to the blaze late Saturday.
The fire burned over a Minuteman missile site, Weber said. But the missiles, buried in underground silos, are protected by thick reinforced concrete slabs.
About 75 people were evacuated Friday night from the small towns of Utica and Sapphire Village, a few miles south of Windham, Weber said.
For a time, U.S. Highway 87, the main highway through the area, was closed for 45 miles between Stanford and Lewistown.