Wind River Canyon Rockslide Changes Timeline for WYDOT Road & Rock Projects

There is a flurry of activity in the Wind River Canyon as W.Y.D.O.T. moves up the timeline for essential mitigation projects after last weekend’s rockslide – which means 30+ minute delays this summer.

Last Saturday’s rockslide closed the section of US20/WY789 running through the Wind River Canyon for four hours. Because of this, W.Y.D.O.T. isn’t taking any chances and is getting down to business.

The recent rockslide is “forcing early mobilization for prime contractor Oftedal Construction, Inc., of Casper and its rockslide mitigation subcontractor for the second year of a slide stabilization project.”

The $8.78 million slide stabilization project started last year. Its scope includes slide repair, grading, slide stabilization rock (SSR), manual rock scaling, rockfall mitigation, and other work on US20/WY789 beginning at milepost 115.9 through 123.12 inside the canyon between Shoshoni and Thermopolis.

Courtesy WYDOT District 5

W.Y.D.OT.’s current concern is much larger rocks already poised to fall onto the highway.

“Oftedal is moving in equipment to move the current talus rock that fell on the highway Saturday, so other rocks on the slope have a place to fall that’s not on the highway,” said Wyoming Department of Transportation project engineer Jordan Erz of Worland. “Midwest workers will then perform rock scaling work on that area to hopefully remove all the loose rock. There are also a few big rocks above the road that thankfully did not fall Saturday night. These big rocks must be moved to the roadway as soon as possible to make that area as safe as possible.”

Oftedal Construction completed rock mitigation rock near the Buffalo Bill Dam in 2019. The large chain-link structures are intended to stop rocks before they crash onto the highway.

There is now much urgency for both Oftedal Construction and the subcontractor – Midwest Rockfall, Inc., of Henderson, Colorado – to clear and secure the rockslide area. As a result, Midwest Rockfall personnel were on-site on Tuesday, April 26.

Some of Midwest Rockfall’s rockfall mitigation work remains from the original contract. Now,  the subcontractor’s work will also include emergency tasks at the location of the April 23 rockslide.

Other work in the contract includes:

• Installing a rock attenuator system
• Installation of rock bolts
• Repair of existing rock fence
• Installation of new rock mesh

Erz said the big rocks above the roadway from Saturday’s rockslide are sitting in fragile areas and could move downhill on their own. The expedited work schedule is “a proactive decision to enhance human safety and avoid further damage to the roadway.”

Several other road projects are also planned for the Wind River Canyon in 2022.

Oftedal will be installing three new pipes later this year. The pipes are intended to move runoff water on the rock mitigation project.

At the same time, southeast of Wind River Canyon, asphalt paving began this week. The work zone covers 8.36 miles of US20/WY789 between the town limits of Shoshoni and Birdseye Road, between Shoshoni and Wind River Canyon.

When paving is complete north of Shoshoni, Mountain Construction will be paving the Upper Wind River Campground in separate work for Boysen State Park. That work on the campground roadways could also add to the length of the traffic delays between Shoshoni and Thermopolis.

With the projects so close to each other, motorists should expect combined stop delays of up to 35 minutes through the $4.74 million paving project and slide cleanup effort.