News June 12, 2018

Bridger-Teton National Forest Opens Bypass Route around Porcupine Landslide Near Alpine

by Jackson Hole. Media

The Greys River District of the Bridger-Teton National Forest has opened a temporary bypass route around the Porcupine Landslide on Tuesday June 12, 2018, much sooner than originally anticipated. The Forest has removed hazard trees and appropriately signed the route to provide two-lane motorized access acceptable for passenger cars travel to the area around the landslide. The bypass route does included some narrow ‘S’ turns and while navigable by vehicles pulling trailers, it will require slower travel speeds. Work will be ongoing this summer to install the permanent sections of the Greys River Road which were obliterated by the landslide. The Forest hopes to have the Greys River Road repaired and the bypass route reclaimed before the end of 2018.


The area closure has been completely rescinded with no restrictions or closures. Geotechnical drilling shows the slide material is sufficient for the temporary route construction and allowed for the adjustment to the risk analysis, providing the District Ranger with the necessary evidence to lift the closure order. While the debris dam created by the landslide still impounds approximately 12-feet of water, the Wild and Scenic eligible Greys River has cut a new channel and widened the river to 40-feet at its narrowest part. Camping is now allowed within the first 7-miles of the Greys River corridor which is the standard for the corridor, pre landslide. The drainage and culverts that were installed have facilitated dewatering the site which has slowed the landslide significantly and stabilized the slide sufficiently to allow the contractors to install the road. There may be additional travel restrictions later during the construction of the permanent route. There is no instream work anticipated for the repair work.


Several partners provided equipment, material and expertise to expedite the installation and opening of the bypass route including JR Simplot Smokey Canyon Mine, Wyoming Department of Transportation and Lincoln County, Wyoming. “We could not have done this expedited work without their skills and generosity and are immensely grateful for their cooperation,” said Greys River District Ranger Justin Laycock. The Forest is in the final stages of being able to select a contractor who will work on reinstalling the Greys River Road and with anticipated good weather, possibly also commencing work on the Blind Bull landslide which occurred in 2017 in the neighboring vicinity.


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