NORTH WOODSTOCK, N.H. (AP) — A brush fire near the popular Lost river Gorge and Boulder Caves in New Hampshire has spread to over 20 acres and closed part of a hiking path along the Appalachian Trail.

Firefighters say the fire started on a cliff in Kinsman Ridge over the gorge Tuesday morning and spread overnight. They aren't sure of the cause; one theory is that it might have been caused by a meteor. Crews have been dropping water from helicopters, including a Blackhawk.

Fire officials estimate it could take several days to put out the fire, which is in rugged terrain.

Lost River Gorge was closed Tuesday as a precaution, but reopened Wednesday.

Forest officials closed part of the Kinsman Ridge Trail and surrounding areas.