Superintendent Mary Risser announced that the Jones Hole Trail will reopen today, August 10, 2013 at 6:00 am. 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.
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," stated Superintendent Risser. "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 ¼ 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 that 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," expressed Superintendent Risser.
During several events between June 18 and June 20, 2013, over 2400 m3 (3140 yd3) of rock estimated to weigh over 6,000 metric tonnes (6,600 tn) was released from Weber Sandstone cliffs. The rock fell from a height of 340 m (1,115 ft) into and across Jones Hole Creek about 600 m (1970 ft) 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's 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, please call (435) 781-7700.