Officials says the Pine Creek Fire is estimated at about 1,500 acres in size and is burning in grass and pine trees in the Grimes Creek area.
Firefighters are responding with three 20-person crews, three helicopters, four engines, six single engine air tankers and two heavy air tankers.
No structures are threatened by the fire currently.
Idaho Department of Lands officials say Grimes Creek Road is open to local traffic only, but it could be closed again because of the danger of rolling rocks and falling tree limbs.
Kathy Hatfield of Melba was camping with her family when firefighters told her she had to leave immediately -- leaving behind personal belongings.
"Everyone was going down the road screaming and yelling 'fire, fire'" Hatfield said.
The family had to leave all their tents, food and a trailer behind.
Travelers along Highway 21 in the vicinity of the fire are asked to use caution as smoke may be heavy on the highway at times. The cause of the fire is under investigation, but is believed to be human caused. ----> Photos of the Fire
Heavy smoke in the area earlier this morning limited aircraft use for suppression efforts, but by early afternoon smoke had cleared enough that air tankers and helicopters could work on water drops.
No structures are threatened.
Approximately 260 fire personnel are working to suppress the fire, including nine 20-person hand crews, nine engines, and one dozer, plus air support.
The Papoose Fire in the Salmon-Challis National Forest has grown to more than 4,400 acres.
The fire is burning primarily in the Middle Fork river corridor, burning across the slope and backing downhill toward the river. Visitors in the area are asked to use caution while traveling in the area.
Idaho Department of Lands officials say they are responding to eight new lightning-sparked fires in the forests of southwest Idaho.