400-Foot Rockfall Closes Trail At Dinosaur National Monument

A large rockfall at Dinosaur National Monument has prompted a temporary closure of a stretch of the Jones Hole Trail. NPS photos.

Repeated rockfalls, including one that featured pickup-truck-sized boulders that fell as much as 400 feet, have forced Dinosaur National Monument officials to close a stretch of the popular Jones Hole Trail.

For the immediate future, the trail and surrounding Park Service lands from the Park Service-U.S. Fish and Wildlife Service fish hatchery boundary to Ely Creek are closed to all public use, monument Superintendent Mary Risser announced Thursday.

The first reported rock slide occurred on Tuesday when a large slab of rock broke free from a cliff face just a short distance inside the monument boundary, less than quarter-mile from the Jones Hole Fish Hatchery.

"One fisherman reported having to run from a boulder that landed in the stream not too far from his location," the park said in a release.

While a check by rangers failed to spot any further slide activity, on Thursday morning another small slide occurred. Then near noon local time a larger slab of rock tumbled to the stream below, the monument staff reported.

"A large debris field formed below the slide site. The slide was large enough to send large boulders, the size of a pickup truck, across Jones Hole Creek before coming to rest against trees by the hiking trail," the park's release said. "The surrounding area is covered with a layer of dust from the slide. No injuries were reported as a result of the slide."

Park staff said the rock face that broke free from the cliff "is roughly estimated to be 100 feet high by 50 feet wide with a thickness of 10 feet or more. The slab fell over 400 feet to the slope and stream below."

"Numerous trees were knocked down during the event including several across the trail. Large cracks are visible in the rock remaining attached to the cliff. The area will remain closed until further notice," the park release said.

The Jones Hole Trail is a popular hiking trail that connects the Jones Hole Fish Hatchery with the Green River. It is approximately 4.25 miles long one way. The area is also very popular with anglers due to the access to Jones Hole Creek.

Hikers or anglers who violate the closure order could face fines.