The fire was in a rugged area within the Cibola National Forest near Mt. Sedgwick in western New Mexico.
``It's growing on us,'' said Chuck Hagerdon, the Mount Taylor District ranger.
At one point, firefighters were pulled back because the fire was acting too erratically.
No structures were threatened, Hagerdon said, but the Ojo Redondo campground was evacuated. The campground is south of where the fire was burning.
The fire was burning 14 miles west of Grants in Diener Canyon, a popular recreation area. Hagerdon said a campground not far from the fire was evacuated by Cibola County Sheriff's officers
The fire was reported at about 2:30 p.m. Saturday and rapidly gained momentum. It was burning in an area that Hagerdon described as ``probably the most rugged terrain in the Zuni Mountains.
``It's very rugged, very steep and with very few usable roads,'' he said.
Hagerdon said the fire was about eight air miles south of Bluewater Lake. Residences in the Bluewater Lake area and in a subdivision about 10 air miles south of the fire were not in any danger, Hagerdon said.
About 75 people were fighting the fire Saturday. Hagerdon said firefighting crews were using five engines, four helicopters and four single-engine air tankers. Two Air Force C-130 aircraft from Arizona dropped over 5,000 gallons of fire retardant on the fire.
He said two Type 1 and two Type 2 firefighting crews had been called in, but they weren't expected to be on the fire line until Sunday. Each crew has 20 people on it.
What started the fire had not been determined, but Hagerdon speculated it might have been human-caused because there has not been any lightning in that area.
The fire had sparse fuel when it started but spread quickly uphill into heavier timber. It was burning through mostly ponderosa trees, along with mixed conifers.