idaho Wildfire School

New wildland firefighters fight a blaze during a training session in June 2014 in the Sawtooth Mountains north of Fairfield, Idaho. Meanwhile, a real wildfire in central Idaho has forced the evacuation of backcountry campers in the Sawtooth Wildneress and an increase in firefighting crews and equipment.

(Associated Press)

BOISE, Idaho — About 20 backcountry campers in the

had to be evacuated because of a central Idaho wildfire that several hundred firefighters are trying to snuff out before it gets too large.

More crews and equipment arrived Saturday to fight the

burning through dead and downed trees about 12 miles south of Stanley, fire spokeswoman Barbara Bassler said.

Large air tankers are also taking part Saturday, officials said, to protect nearby cabins and trailers. There were no reports of injuries or any damage to structures.

The fire that started Friday afternoon reached about 130 acres Saturday morning.

Air tankers and helicopters worked Friday to slow the fire's growth until ground crews could arrive to start building fire lines, Bassler said.

"They're actively working to contain it," she said. "With the amount of bug kill up here, you don't want to just let this go. We have the resources, so we are suppressing the fire."

Fire managers, however, have given no estimate for when it might be contained.

The fire is believed to be caused by people because there was no lightning in the area at the time, Bassler said. A fire investigator has been called to determine what happened.

Firefighters are having success on the east side, where the flames have reached grass, Bassler said. But it's not as easy in the timbered, mountainous area on the west side of the fire, she said.

"They're putting everything they can at it, with the priority the safety of the firefighters," she said. "There are lots of snags. We don't want to risk any loss of life."

Two hotshot crews from Montana are assigned to the blaze, she said.

The mountainous area is a favorite among tourist this time of year, arriving for the hiking, rafting, rock climbing, mountain biking, fishing and other activities.

The last two summers, though, businesses lost customers because of fires in the region that grew.

"We certainly understand the concern of the people up here," Bassler said. "I know people are quite nervous. We are getting resources here, and we are aggressively fighting the fire."

Idaho Highway 75, which is part of the state's scenic byway system and cuts through the middle of the high-elevation valley bracketed by mountains, is open. Road 210 into the forest is closed, however.