BOULDER, Mont. (AP) _ Firefighters have made progress on blazes burning in the scenic Bitterroot Valley in western Montana, but evacuation orders remained in effect for approximately 1,400 households.

Elsewhere, hundreds of evacuees were allowed to return home Sunday as a few days of cooler weather allowed firefighters to gain the upper hand on two wildfires south of Helena, as well as a fire in the Big Hole Valley.

And a U.S. Army crew from Fort Hood, Texas, was called in to help with fires in the upper Ninemile Valley near Missoula, where winds began fanning flames that have burned a total of 12,400 acres.

So far this fire season, more than 375,000 acres of Montana have burned _ an area larger than the city of Los Angeles _ and 169 buildings, including more than 50 homes, have been lost.

In Nevada, a pilot was killed Sunday when his helicopter crashed while he was making water drops on a wildfire. The blaze, in a remote about 50 miles east of Fallon, had already consumed 37,700 acres.

The pilot was the eighth firefighter killed fighting wildfires this year, and the second Nevada-based firefighter killed in a helicopter crash within 10 days.

``In some cases, we're having to let a lot of acreage burn because we simply don't have the available resources to control the fire without jeopardizing the safety of firefighters,'' said Dan O'Brien, the federal interagency coordinator for the fires.

A stretch of Interstate 90 across western Montana was closed for about an hour, and traffic was escorted through the area for several more hours as winds blew embers across the four-lane highway.

``The fire has, over the last couple of days, been burning very intensely. We can see columns of smoke here in Missoula'' about 30 miles away, said Marcia Hogan of the Southwest Montana Coordination Center.

The news was better south of Helena, where people forced to flee 270 homes because of the threat from two fires in the Elkhorn Mountains were allowed to return home Sunday.

``It looks like the main action is not coming toward the valley, but a shift in the wind and we're back to the races again,'' said Jack de Golia of the U.S. Forest Service.

Firefighters reported progress in the Bitterroot Valley, where one cluster of fires south of Hamilton had burned 112,000 acres and another north of Hamilton had charred 8,990 acres.

A couple of days with cooler temperatures and little or no wind gave firefighters a chance to concentrate on building more containment lines, said Mike Odegard, a fire information officer.

``So far, so good,'' he said Sunday. ``The fires are kind of sitting on themselves, not making any runs.''

There were 76 major fires burning Sunday in Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, South Dakota, Texas, Utah, Washington and Wyoming, the fire center said. Those blazes had blackened about 869,000 acres.

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On the Net:

National Interagency Fire Center: http://www.nifc.gov

Forest Service: http://www.fs.fed.us/fire/news.shtml