Dinosaur National Monument’s geology, which was made famous by the fossils hidden in its sandstone and shale rock formations, made the news again as a large rock slide hit the Jones Hole area--less than a quarter of a mile from a U.S. fish and Wildlife fish hatchery. The first slide happened on Tuesday June 18, but the area did not close down until a larger slide on Thursday June 20.
"On Thursday we got another report of another small slide and then very shortly after, at noon, a report of a large slide coming off of there that actually sent boulders across the creek, onto the trail, and caused a lot of trees to go down. It fell probably about 400 feet," said Dan Johnson, chief of visitor services for the Monument.
Though no one was injured in the fall, a fisherman did report having to run from falling boulders during the initial slide on Tuesday. Thursday’s slide left boulders the size of pickup trucks scattered in the area. Johnson said overhanging rocks are still located on the cliff face and that more slides are possible.
Though these rock slides can be dangerous, they are what Johnson describes as a natural geologic process that is likely caused by the heating and expansion of the rocks—which span 1.1 billion years of Earth’s history.
Johnson said the monument is waiting for an expert opinion on the safety of the area before they reopen the trail and creek to the public.