By Jerry Purvis
news@geringcitizen.com
Over the weekend of Jan. 9-10, a rockslide closed a section of the Saddle Rock Trail at Scotts Bluff National Monument.
Staff originally thought it would take several days to clear away the debris. However, the work was done in one day on Jan. 13 by three rangers and one volunteer.
Chief Ranger Mark Davison said the rockslides usually happen during the winter and spring, when there are more widespread changes in temperature.
“Water gets into cracks in the rock and freezes,” he said. “That loosens up the limestone and increases the chances of slides.”
Bob Manasek, the Monument’s Resource Management Specialist, said the early heavy snowfall in October melted in about three days. That contributed to more water getting into cracks in the sedimentary rocks that make up the Monument.
“As the water freezes and thaws, it expands and contracts,” he said. “I think that as the rocks near the surface weather, it’s more likely for water to get in.”
Manasek said another major rockslide occurred in the same general location about eight years ago on the upper part of the trail, above the tunnel on the hiking trail.
“That one was huge and just buried the trail,” he said. “That debris had to be blasted out.”
Park Service geologists analyzed the rockslide at that time and concluded there was no way to predict when another slide would occur.
“That’s kind of discomforting,” Manasek said, “but a lot of the slides have occurred in the evening after the trail is closed.”
Davison said the latest slide covered three sections of trail along the switchbacks. Upon inspection, he said the debris was about 23 feet wide and stacked up about four feet. Both smaller debris and numerous larger boulders were part of the slide.
Using pry bars, the four-person cleanup crew has to push the debris down from the top switchback to the next and work down. In all, about four sections of trail had to be cleared.
“They got the work done a lot faster than any of us thought,” Davison said. “I thought it would have taken several more days. I was surprised when they called and said the trail was ready to be opened again.”
Manasek said there will still be some settling along the slide area as smaller loose debris is washed out by rain and snow.