Firefighters declared a temporary victory Friday in their battle to keep a forest fire out of a small Montana town, and forest officials warned that more lightning and dry, hot weather were forecast this weekend.

"It's like sitting on a time bomb," said Scott Phillips, recreation officer for the Sawtooth National Recreation Area in central Idaho. "If we can get through this weekend without a conflagration, it will be a miracle."Forests and rangeland burned Friday in parts of Wyoming, especially in Yellowstone National Park, and in Idaho, Montana, Oregon, Washington, Utah and California.

The Boise Interagency Fire Center, the logistics command for the national battle against forest fires, reported more than 25,000 firefighters, military and support personnel on the lines of more than three dozen major fires in the West.

Fire Center spokesman Arnold Hartigan called it "the most severe fire season in almost 30 years." More than 3.5 million acres have burned, two-thirds of that in Alaska, and suppression costs already exceed $250 million.

"The fire season is anything but over. . . . The 30-day weather forecast calls for continued unseasonably hot and dry weather for the Pacific Northwest and northern Rockies," Hartigan said.

The focus of attention Friday in and around Yellowstone, where some 550,000 acres have been charred, was the small town of West Yellowstone, Mont., just outside the park's west entrance. It was threatened by flames just over a mile away that were spreading from the 118,000-acre North Fork fire inside the park that had grown by nearly 10,000 acres since Thursday morning.

Bulldozers, helicopters and back fires stalled the advance of the fire Friday. But gusty winds swept a swath of flame south of the town and a wind change predicted for Monday raised concerns the blaze could move back toward the community.

"In my judgment this community is very defensible," Denny Bungartz, the North Fork fire's incident commander, told about 60 townspeople.

He said fire trucks had pumped 5,000 gallons of water into dry brush around a warehouse at the park boundary, and 50 fire engines would be in town during the night to hose down buildings if necessary.