Final fix for Teton Pass landslide will require a weekend closure

Yahoo

13-06-2025

Crews are nearly finished rebuilding the section of highway that collapsed last year on Teton Pass. To guard against future landslides, the project has installed drainage, stitched the base together with micropiles and used lighter-weight material to complete the "Big Fill." (Photo courtesy of the Wyoming Department of Transportation)
Closing Wyoming's busiest two-lane highway for two-and-a-half days during the height of the summer tourism season will disrupt travel for thousands of commuters and visitors who rely on Teton Pass. But the alternative would be worse.
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'You never want to close the road, but a two-day closure has a lot less impact on everyone,' said Bob Hammond, resident engineer with the Wyoming Department of Transportation. WYDOT plans to close the road to traffic during the weekend of June 21.
Without the closure, work needed to finish fixing the 'Big Fill' landslide — last year's catastrophic failure of a 30-yard chunk of Wyoming Highway 22 over the steep mountain pass — could stretch over 10 days or more. Keeping the road open during construction would mean resorting to one, alternating lane of travel.
'It would just back up horribly,' Hammond said of the traffic that would result.
During peak traffic hours, delays could be so substantial that motorists might opt for the longer detour anyway. When the mountain pass closes, commuters from the Idaho side of the Teton Range, where housing is cheaper than Jackson Hole, typically re-route their daily travel through Swan Valley, Alpine and the Snake River Canyon. That adds roughly 1 hour and 6 minutes to what is usually a 24-mile and 32-minute drive.
Community stakeholders have generally agreed that it's best to end the disruption quickly, said Stephanie Harsha, a WYDOT public relations specialist who has been working with Teton County organizations to get the word out about the closure slated for 6 p.m., June 20, through 6 a.m. June 23.
'I think people understand how we came to the decision,' Harsha said. 'We're very thankful for their support. When we do close it, we are disrupting commerce and the economy because there are so many commuters. We understand the impact it has in the area.'
Crews will work 24 hours a day to expedite milling, grading, placing crushed base and paving. They'll also install guardrails and signs.
The highway will be closed between the Coal Creek Campground on the west side and the gate at mile marker 7 on the east side. People can still bike and otherwise recreate on the east side of Teton Pass and access the Coal Creek Campground on the west side. But WYDOT is warning walkers and bikers to beware of heavy trucks and not descend from the top of the pass down the west side toward the Big Fill work site.
The June 7, 2024, landslide made national news, spurring local businesses to reassure visitors they could still reach Grand Teton and Yellowstone national parks. But the closure also highlighted the vulnerabilities of a mountain community's robust tourism and lifestyle economy.
That so much depends on a single road became evident just last week when a trailer lost its load on Highway 22, blocking both lanes of travel near the Snake River bridge.
On June 5, Hammond started receiving texts from contractors working in Teton County on a second major WYDOT project, building a new four-lane bridge over the Snake River between Jackson and Wilson. The multi-year, $60 million bridge reconstruction and intersection redesign is expected to wrap up in July.
A log cabin fell off a trailer, 'at least twice,' including on the WYDOT jobsite. Crews moved some concrete barriers to give the abode a temporary home.
'We were able to get that cabin off the road to get the lanes open,' Hammond said. 'Otherwise, it was blocking the entire road.'
The transport company had tried to move the Etna-bound cabin in the middle of the night but quickly ran into trouble, the Jackson Hole News and Guide reported Friday. The sudden sight of a cabin taking up residence on the bridge spawned some humor on social media, with commenters posting on Facebook, 'rent is 3k as it sits'; 'Hey you can't park there' and 'someone move in, squatters rights!'
But it also seriously snarled the morning commute, backing eastbound traffic all the way up Teton Pass and disrupting travel for workers, visitors and school kids, who had their tardies excused. Even after the road reopened, it took another four hours to clear the congestion, Hammond said. The cabin was finally removed Saturday morning, he said, 'before everyone was up.'
Although unrelated to the Teton Pass project, the cabin debacle shows how long it can take to clear traffic once commuters from Idaho get stacked up, Hammond said.
Highway 22 between Jackson and Teton Village Road sees about 18,000 vehicles per day on average — but 24,000 in July and August with a peak of 27,000, according to WYDOT data. The stretch over Teton Pass to the Idaho state line sees an average of 10,000 vehicles per day. In the height of summer, daily trips jump to around 16,000 west of Teton Village Road and 10,000 east of Victor, Idaho. For comparison, the divided four-lane stretch of Interstate 80 between Green River and Rock Springs accommodates an annual average of 25,000 vehicles per day.
Knowing how any disruption can create problems on the busy Teton corridor, WYDOT wanted to give at least two weeks advance notice of the upcoming weekend pass closure so workers could plan ahead.
'We wanted to give them an opportunity to maybe set up an alternate schedule,' Hammond said. 'We can't really reach all the tourists, but we'll be putting up variable messaging signs.'
After the road first failed, WYDOT contracted for $900,000 with Evans Construction to put in an emergency detour. That got the vital highway reopened within 20 days. Now Ames Construction is putting the finishing touches on the permanent fix to the tune of about $43 million.
The detour functioned well but has an 11.3% grade and a 20-mph speed limit. The rebuild follows the original, more gentle contour that uses fill material to create a bridge between two hills, hence the name 'Big Fill.' The speed limit will return to 45 mph with a speed advisory that likely will be set at 35 mph, Hammond said.
Although WYDOT had observed movement there for decades, Hammond said, 'it wasn't a big concern until it was. When it slid out.'
WYDOT hired a geotechnical engineer with experience working on landslides around the country and has taken steps to avert future problems.
The three factors that contributed to the slide were lubrication, too much weight 'or driving force' on top of the fill and too little 'resisting force' holding the bottom together, Hammond said.
'When you get all three together, that's typically when landslides happen,' he said.
So crews have inserted drains at the base of the fill so groundwater doesn't pool there like it did before. Workers have excavated and drilled 'micro piles' — steel rods inside a casing — in a pattern to stitch together the ground beneath the new fill to increase 'resisting force.' To reduce 'driving force,' the new fill includes lightweight material that cuts the total weight in half to around 60 pounds per cubic foot compared to the typical 120-125 pounds per cubic foot, Hammond said.
Hammond credits both Evans and Ames with getting the job done quickly in the face of catastrophe.
'We got some contractors who understood what they had to do and how important it was,' he said.
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