Idaho Highway 75 was closed Saturday afternoon as part of precautions taken with the Hell Roaring fire south of Stanley.
The highway is closed at National Forest Road 210, northeast of Yellowbelly Lake. The closure continues several miles north to a point near the Williams Creek trailhead. Forest Service Road 210 along with several trails are also closed.
No one was available Saturday afternoon at Sawtooth National Forest offices to talk about the closures. Officials were still at the fire scene.
A map of the closure area can be found here.
About 20 backcountry campers in the Sawtooth Wilderness had to be evacuated.
More crews and equipment arrived Saturday to fight the Hell Roaring Fire 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."
Nearly 200 firefighters are tackling the blaze. They're assisted by four helicopters and four engines.