Zion National Park has closed its backcountry to hiking, climbing and rappelling, as of Thursday, July 19. The park is located in southern Utah, 150 miles north of Las Vegas.

Fires have burned approximately 8,000 acres, or 12.5 square miles, producing thick smoke in canyons in evening and early morning when temperatures drop.

Firefighters parachuted into the remote backcountry or were dropped in by helicopter Wednesday but were airlifted out soon after.

The main trails in the park's Zion Canyon are still open.