Leadership of the Wyoming Department of Transportation say a mudslide that wiped out Highway 22 on Teton Pass last year was an unavoidable event, caused by extreme, fast-changing weather conditions.
WYDOT Director Darin Westby and Chief Engineer Keith Fulton defended their agency’s handling of the event while speaking to the Joint Transportation, Highways and Military Affairs Committee.
They also offered new details about the reconstruction of the mountain and highway, as well as work to repair the Green River Tunnel, which suffered a catastrophic fire earlier this year.
On June 8, 2024, a large chunk of the mountain holding up part of Teton Pass slid away from under Highway 22, sending it into the ravine below. This and the full-blast, 24/7 road reconstruction effort that followed to rebuild the mountain and the road has been dubbed the “Big Fill Slide.”
After initially noticing some damage on Highway 22 prior to the slide, WYDOT closed the road and made a plan to monitor it before reopening. The next day, a mudslide happened about 3 miles away on the Idaho side of the highway, which closed the pass.
Two days after that, what Fulton described as “an unexpected long-term failure” on the road took place — with a large section of Highway 22 collapsing down the side of the mountain.
The actual mudslide that caused the collapse was triggered several thousand feet up the mountain from where the road was eventually wiped out, leaving several feet of mud over the top of the highway, he said.
Shortly after the slide, Gov. Mark Gordon issued an emergency declaration, allowing WYDOT to be able to apply with the federal government for emergency repair money.
“That’s a pot of funds where we can get reimbursed for all the costs,” Fulton said.
Under this program, for the first 180 days after an event, the feds will reimburse 100% of all costs. After that, the costs move to a 50/50 split with the state.
A box culvert was installed on Teton Pass by WYDOT to better channel mud during future runoff and high moisture events. This came at a cost of $1.4 million.
Crews have been working around the clock to repair what WYDOT has called a "catastrophic" failure of Highway 22 over Teton Pass. (WYDOT Teton County via Facebook) 
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 mudslide at about 4:20 a.m. Thursday morning has shut down Wyoming Highway 22 over Teton Pass at milepost 15. The closure comes less than 24 after a large two-lane crack in the pavement of the highway closed the pass for a few hours. (WYDOT Teton County via Facebook) 
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) 
Crews have been working around the clock to repair what WYDOT has called a "catastrophic" failure of Highway 22 over Teton Pass. (WYDOT Teton County via Facebook) 
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) 
Vehicles are driving on the new temporary fix for the June 8 catastrophic failure of Highway 22 over Teton Pass. (Wyoming Department of Transportation via YouTube) 
Work is going quickly at the S curve that failed on Teton Pass over the weekend. (WYDOT Teton County) 
A Teton Pass bypass fix works for now, but engineers say it is not the long-term solution. (Courtesy Wyoming Department of Transportation)
So, What’s Being Done Differently?
State Sen. John Kolb, R-Rock Springs, questioned if any similar landscapes exist in Wyoming that could use a similar installment to avoid another catastrophe like what happened to Teton Pass.
“Have we identified anything else that falls under this kind of a classification of a need?” he questioned. “What are we doing to avoid this from happening again somewhere else?”
Fulton said his geology staff tries to monitor for these types of situations, using various pieces of equipment like inclinometers. They’ve already taken action in certain spots like the North Fork Highway outside Cody, where WYDOT installed similar infrastructure.
But he also said performing work like this in high alpine environments is difficult.
“These are hard to do because most of these slides happen right up out of our right of way and several thousand feet above the highway,” he said.
No Movement Before Slide
Westby added that WYDOT had been monitoring the fill above the road that led to the slide two weeks prior, with no movement identified at that time.
“There was absolutely no movement in that hill,” he said. “It went from no movement to slid in like two weeks.”
But in many cases, Fulton said WYDOT’s only option is to react to disaster events rather than proactively mitigate risks.
Kolb said he understands this approach, but countered that “obviously, what we’re doing didn’t work” and continued to question WYDOT leadership about what they’re doing differently to prevent future slides.
Performing mitigation after an event, he pointed out, comes at a much higher cost.
“What are we doing to get ahead of these things before they (end in) a catastrophe?” Kolb questioned.
Fulton reaffirmed that his staff is continuing to monitor for these risks and have a few projects up their sleeves to address areas that look like they'd be prone to a slide.
“We try to get them in when we think they’ll be almost catastrophic event,” he said. “We can only do so much with the funding that we have to preserve our roads.”
Rep. Landon Brown, R-Cheyenne, defended the way WYDOT handled this event, mentioning how it’s not always possible to plan for extreme weather events.
He thanked Fulton and Westby for their work and mentioned how Tom DeHoff, WYDOT assistant chief engineer for operations, was up for about three straight nights after the slide occurred working on the problem.
“Mother Nature plays a role in what happened there,” Brown said. “Sometimes we don’t have ability to fix Mother Nature and her destructive fury.”
Slides of various sizes happen every year on Wyoming roads, particularly in the northeastern region of the state, Westby said. WYDOT is now working on a realignment project that came about because of a slide on Interstate 90.
Rebuilding Efforts
Two days after the Highway 22 collapse, WYDOT started developing plans for a temporary detour route to get the road back open, and on June 28, 2024, they accomplished that — just 20 days after the slide wiped out the road.
“Great work from our district and our contractors and our locals to get that done,” Fulton said.
About one week after the slide, WYDOT also issued a request for proposals for a permanent reconstruction of the road. The agency decided to build the road back as it had been prior to the slide.
Fulton said some members of the public questioned why they didn’t move the road to avoid future slides. Doing so would’ve increased Highway 22’s 10% grade to 22%, or required the construction of another horseshoe switchback in the road, he said.
“The decision was made (to) let’s put it back and let’s fix it so we don’t have to deal with this again in the future,” he said.
The actual work on this part of the project started in September, with work continuing through Dec. 16. Fulton said the work stopped at this point because the quantity of snow became too much to overcome.
But work has already started back up this spring, he said.
“Pretty impressive work,” Brown said.
Stabilizing the slopes above the incident cost about $11 million and installing drainage pipes and various foam glass aggregates for the base of the road cost another $30 million, Fulton said.
More than a month after a devastating 26-vehicle crash and fire inside the westbound Green River Tunnel, cleanup is still underway. (Wyoming Department of Transportation) 
An investigation is underway at the Green River Tunnel along Interstate 80 after a fatal multi-vehicle crash sparked explosions and an intense fire inside Friday, Feb. 14, 2025. (Wyoming Department of Transportation) 
From the charred westbound lane of the Green River Tunnel on Monday, Feb. 17, 2025. (Clair McFarland, Cowboy State Daily) 
Friday's crash inside the westbound Green River Tunnel killed three people, officials confirmed as the final death toll. (Wyoming Department of Transportation) 
Heavy, black smoke continues to billow out of both ends of the Green River tunnels along Interstate 80 after a fatal multivehicle pileup and fire inside Friday afternoon. People in traffic report “huge explosions.” (Wyoming Department of Transportation via Webcam) 
Traffic is moving through the Green River Tunnel again Thursday, Feb., 20, 2025, but at a lower speed. Authorities also caution to expect delays. (Wyoming Department of Transportation)
Green River Tunnel Rebuild
Fulton said it’s WYDOT’s goal to get the Green River Tunnel fully reopened by the winter.
On Feb. 14, a chain-reaction crash on I-80 damaged the Green River Tunnel, involving 26 vehicles and causing three deaths. Brown commended the work of an off-duty Wyoming Highway Patrol trooper who rescued a number of people from the tunnel that day.
Due to the fire in the tunnel, WYDOT had to immediately close both lanes of the Interstate, detouring traffic through the city of Green River.
The tunnel still hasn’t fully reopened and large trucks are still being directed through the city at times, an arrangement Kolb and Brown said has caused some concerns from Green River residents and what it will cost them if they have to pay for any road mitigation.
“I think there’s a lot of concern of when they actual determine what the expected outcome of how long this tunnel is expected to be closed, there’s a lot of concern of what this is going to do to that main road,” Brown said, adding there’s a lot more truck traffic now on other roads in Green River as well, which he’s “sure their road is getting beat to the living tar.”
Fulton admitted this has led to significantly more traffic in the city. But he also said the detour road was already under WYDOT management and they have been actively patching holes in it, a commitment Kolb demanded continue.
On Feb. 15, WYDOT was able to get its first look at the inside of the tunnels and five days later reopened the eastbound side for traffic headed in both directions by reducing it to one lane each way.
Fulton said various issues with this arrangement and pressures from the increased load of traffic have led to sporadic re-closures of the tunnel.
It wasn’t until March 17 that a WYDOT-contracted company was finally able to get in the tunnel and remove all the burned vehicles. It also removed concrete tunnel liners and lights damaged by the fire, with that work completing April 6.
The next day, WYDOT and federal officials performed a full inspection of the tunnel, performing a 3D scan to address areas of potential concern. They’re still working on a final inspection report and performing tests to determine the tunnel’s integrity.
Fulton said WYDOT knows that the tunnel road is damaged on the westbound side but doesn’t know yet to what extent. The agency also plans to install a whole new lighting system.
So far, $1 million has been spent on the project.
Wildfires
Fulton also said WYDOT lost a lot of signs and miles of guardrail during the catastrophic wildfire season in 2024, which has cost about $1 million to replace so far.
The House Draw Fire in Johnson County last August damaged about 14 miles of fence along I-90, Fulton said, as well as damage to signs.
The Elk Fire on U.S. Highway 14 near Dayton led to a closure of the road for 24 days and damage to guardrails on it. WYDOT ended up replacing 8 miles of guardrail and traffic signs here.
WYDOT continues to monitor the road for potential mudslides and erosion made more likely because of the fire damage.
Fulton said coordination between local officials and his staff during all these events has been great.
“People always rise to the occasion, and we’ve seen that through the state,” he said.
Leo Wolfson can be reached at leo@cowboystatedaily.com.
