No immediate repairs planned at Porcupine landslide
The Bridger-Teton National Forest has contracted with Jorgensen Associates in Jackson to provide additional risk analysis of the Porcupine landslide, 17 miles upstream from the town of Alpine, Wyoming along the Greys River.
The ongoing monitoring will help keep the forest informed as it makes decisions about access to the area.
“We hired local engineering firm Jorgensen Associates to provide supplementary risk analysis with more of a focus on risk to recreating public,” said Greys River District Ranger Justin Laycock. “The U.S. Army Corps of Engineers (USACE) risk analysis focused on both infrastructure and recreation. We are looking for additional information as our primary concern is the life safety of our recreating public.”
The 17-mile section of the Greys River Road remains closed. Laycock said the earth is unstable. “The only thing holding the rest of the hillside up right now is the unstable earthen mass at the toe of the slide. If you remove the toe then the rest of the slide will come down, making the situation worse,” he stated.
The forest has received $3.2 million from the Emergency Funding for Federally Owned Roads fund. Laycock said the forest applied for and received an additional $1 million to repair the stabilized Blind Bull landslide, which is about 12 miles southeast of the Porcupine slide.
“We will hire a contractor to get moving on the road work for both of these projects, but that hiring won’t occur until at least after spring runoff,” Laycock stated. “Until it melts off there is little we can do. The snow has to get out of there.”
Latest monitoring reports indicate water has cleared a little as debris in Greys River has settled.
Laycock said the river has begun carving a new channel. There is a 10-ft drop off that has already been eroded away in this new channel where the river has cut into the opposite bank. “Along the affected roadway we see fractures more than 3-feet wide and 20-feet deep and those broken chunks of land will most certainly fall into the river and further add to the damming, increasing the amount of water being held back,” he said.
