Update: Garrett Hunter, 13, has been found unharmed.

Pinedale, Wyo. • A search is underway in the mountains of western Wyoming for a 13-year-old boy from Utah who became separated from his Boy Scout group during a backcountry hiking trip.

Sublette County Sheriff's Office Sgt. Travis Bingham says the search for Garrett Hunter, of Draper, intensified Sunday morning.

Bingham says it's been more than 24 hours since the teenager, who has autism, was last seen in the Wind River Range near Elkhart Park.

The scout group had been on a 50-mile, multi-day hike. The area, about 10 miles from Pinedale, is remote but heavily traveled by hikers.

Bingham says members of Hunter’s family and volunteers from Utah have joined in the search, which also includes a helicopter and other aircraft.