A detour built over Teton Pass after part of the mountain collapsed in June, taking part of Wyoming Highway 22 with it, will remain in place over the winter.
The original plan was for a permanent fix of the road to be completed by November, but Bob Hammond, a resident engineer for the Wyoming Department of Transportation’s Jackson office, said that estimate was far too aggressive.
That permanent fix is to rebuild and reinforce the section of mountain that had a catastrophic collapse.
“We had an aggressive schedule of trying to get this done before the snow flies, but really we recognize that’s not going to be the case,” he said. “We’ve got some milestones in there to achieve and most of the items we put in, but we won’t be able to finish it out completely.”
Drivers on the only direct artery connecting Jackson with much of its work force in Idaho will have to wait until next summer for the newly completed Teton Pass and Highway 22.
In the meantime, people will continue to use a detour created on the inside of an old switchback featuring a tighter, steeper curve mitigated with a speed reduction to 20 mph. The paved detour comes with two 12-foot lanes, one in each direction, just like the rest of Highway 22.
Will The Temp Fix Hold?
Although few have questioned the safety of the detour for the relatively mild summer months, driving over the 7,740-foot-high pass in the winter can be a nerve-racking experience when the switchback isn’t tighter on a steeper grade.
The detour is a little bit steeper than the rest of the pass at a 11.2% grade, compared to the 10% grade of the rest of the pass, which Hammond said is a noticeable difference.
That’s also why WYDOT doesn’t consider the detour as a permanent fix.
“Doesn’t sound like much, but it's enough (where) we didn’t want to leave that as a permanent solution,” he said. “We want to get back to the old alignment with a lower grade.”
In addition to the reduced speed limit, Hammond said new guardrails will be put in to replace temporary concrete Jersey barriers that were built on the interior of the original curve away from the unstable slide area. He said the guardrails will allow snowplows to better navigate the tight corridor without having to worry about clipping the concrete barriers.
“We don’t need that to happen either and create a new traffic snarl,” he said.
Also being added to the detour is a chip seal surfacing that will help drivers get better traction on the new pavement. Chains are often required over Teton Pass because of the mountain road’s steep grades and avalanche slide paths.
A “catastrophic failure” of Wyoming Highway 22 over Teton Pass overnight Friday saw a huge section wash down the mountain. A long closure of the “lifeline” between Jackson and Victor, Idaho, is expected. (Wyoming Department of Transportation) 
A “catastrophic failure” of Wyoming Highway 22 over Teton Pass on June 8, 2024, saw a huge section wash down the mountain. A long closure of the “lifeline” between Jackson and Victor, Idaho, is expected. (Wyoming Department of Transportation) 
Huge cracks had formed at milepost 12.8 of Highway 22 over Teton Pass on Friday, June 7, 2024, hours before it failed completely, with a whole section of the highway sliding down the mountain. (Wyoming Department of Transportation) 
Work is going quickly at the S curve that failed on Teton Pass over the weekend. (WYDOT Teton County)
What Happened?
On June 8, a 200-foot section of highway collapsed away from the heavily trafficked mountain pass. Hammond called this landslide, known as the Big Fill Slide, a “perfect storm” even though its risk had been known and mitigated for decades.
“It wasn’t a huge concern, but it clearly goes to show when the right conditions appear, things can happen quickly,” he said.
The department worked around the clock to reopen the pass 20 days later June 28. Although Hammond said this was a difficult time, it also was inspiring.
“I think it proved that we’re capable of moving quickly,” he said.
Even after the detour opened, WYDOT continued to work on it, clearing landslide debris, installing soil nails, traffic control and other dirt work. Then it finally got to start working on the new road.
It wasn’t until mid-August that work started on the permanent fix. Completing paving on the new section of road before winter is unrealistic, Hammond said.
“I know we have a detour that is safe,” Hammond said. “We’ve done modeling on it through computer modeling. We’ve done soils investigations. We’ve done everything we can to make that a safe road for the winter.”
Not First Rodeo
The landslide that ripped out Highway 22 was the third that Hammond has experienced in his career with WYDOT in Teton County.
The first came in 1997 when a landslide ripped through the Snake River Canyon. This prompted then-Gov. Jim Geringer to call up the National Guard to help clear the road of debris. Hammond said fixing the road and reopening it took about six weeks.
An even more serious slide known as Double Draw happened in the same canyon in 2011 that completely wiped out the road. That project took about two weeks.
Hammond said contractors are still on the road every day and will continue working until it becomes too cold. He expects the permanent new section of Teton Pass to be completed by the late spring to early next summer with a hard finish date of July 31, 2025.
Leo Wolfson can be reached at leo@cowboystatedaily.com.
