Jones Hole Trail reopens after slide

DINOSAUR I Dinosaur National Monument Superintendent Mary Risser has announced that the Jones Hole Trail reopened Saturday.
A portion of Jones Hole Creek will remain closed from the NPS/USFWS fish hatchery boundary to downstream of the rock slide zone. Anglers will be able to access the creek either on USFWS property or starting downstream of the slide area to the confluence with the Green River.
While the rock slide remains potentially active, a recent analysis by a geomorphologist with the National Park Service Geologic Resources Division determined that the trail lies on the outer edge of any potential impact zone. Signs will be posted along the trail that inform visitors that they are entering an active slide and should not linger in the area. If they hear cracking or popping noises from the cliff face, they should leave the area immediately.
The portion of the creek below the slide, however, is within the impact zone and due to the greater potential for injury from falling rocks, it will remain closed indefinitely.
“Based upon analysis from our Geologic Resources Division, the risk to anglers in this portion of the creek was quite high,” Risser said. “Unlike hikers who will be quickly moving through this area, anglers may be more stationary, giving them a longer exposure to any falling rocks in the area. Also, the sound of the stream impairs the ability of anglers to hear any cracking or popping sounds that may provide warning of any falling rocks.”
Signs will be posted along the closed section of the creek. Though this quarter-mile section of the creek will remain closed to the public, the remaining 3¾ miles of the creek within Dinosaur National Monument will be open to fishing.
“We know this is a very popular area of the monument and we appreciate everyone’s patience while we worked to ensure that we could safely reopen the trail and creek to monument visitors,” Risser said.
During several events between June 18 and June 20, more than 2,400 cubic meters of rock estimated to weigh over 6,000 metric tons were released from Weber Sandstone cliffs. The rock fell from a height of 1,115 feet into and across Jones Hole Creek about 1,970 feet downstream from the Jones Hole trailhead and National Fish Hatchery.
According to the report received by the monument, the June 2013 rockfall events initiated on parallel fractures or sheeting joints on the cliff. In the absence of clear triggering events, such as intense or long duration rain storms or an earthquake, it is likely that the cause of the rockfall is related to cycles of thermal expansion and contraction caused by diurnal and/or annual changes in temperature or other rock weathering processes, such as frost weathering.
Regardless of the underlying causes, it is likely that there will be more rockfall from this source until the scar more closely resembles previous scar sites, where the majority of the material in front of fracture on the cliff has been cleared. It is not possible to determine how long this process will take.
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.
For more information on Dinosaur National Monument, call (435) 781-7700.