NORTH WOODSTOCK, N.H. — A brush fire near the popular Lost river Gorge and Boulder Caves in New Hampshire has spread to 50 acres.

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 to put out the fire.

Lost River Gorge was closed to visitors on Tuesday as a precaution. Firefighters also used its parking lot as a staging area.

Kate Wetherell, manager of the gorge, said they hoped to reopen on Wednesday.

The cliff climbs a steep 700 feet above the gorge.