VERNON, Ariz. (AP) — A wind-whipped wildfire in northeastern Arizona's White Mountains has charred more than 3 square miles by Thursday evening, authorities said.

The San Juan Fire was reported at about noon southeast of the small community of Vernon, which is about halfway between Springerville and Show Low, and has about 2,500 residents.

The fire had charred about 100 acres by 2 p.m. and grew quickly to 2,000 acres, fanned by wind gusts of up to 45 mph, Apache County officials said.

It was burning in a northeasterly direction into the Apache Sitgreaves National Forest, where ongoing thinning projects "will definitely help slow down any fire activity," forest supervisor Jim Zornes said.

Residents in the areas of Red Cabin Ranch, Whiting Homestead and Green Peaks Hideaway were being advised of a potential nonmandatory evacuation. A dozen structures reportedly were threatened, but it wasn't immediately clear if any were homes.

County officials said a group of Boy Scouts from Gilbert voluntarily evacuated a camp near Green's Peak Hideaway and a group of girls voluntarily left a camp south of Vernon.

The cause of the fire was under investigation.

Sgt. Richard Guinn, Apache County's Emergency Services Coordinator, said authorities have identified the point of origin in a forest area commonly used by campers about 16 or 17 miles east of Show Low.

Four hotshot crews, five heavy air tankers and several engines and bulldozers were battling the fire.

Forest officials said a Type II incident management team, the second-highest level available, will take charge of the fire Friday because of the continuous fuels ahead of the blaze.