“We have lost the northbound lane of the highway, but we are maintaining two-way traffic,” said Wyoming Department of Transportation District Engineer Pete Hallsten of Basin. “Our Cody maintenance crew has filled in the ditch on the uphill side of the highway and surfaced it with mill tailings to provide adequate width for two-way traffic at the present time.”
The moisture-related slide, located near Dead Indian Creek and about 20 miles west of Chief Joseph’s intersection with Wyo. Highway 120, began dropping in March and continues to move.
The area is well marked, with a reduced speed limit and a barrier on the side of the road, Beers said.
“We’re trying to keep them [travelers] off the slide area, because the additional weight tends to push it downhill,” he added.
Chief Joseph doesn’t get much truck traffic, because big trucks can’t go through Yellowstone National Park, he said.
If the hillside continues to slide this spring and summer, Hallsten said WYDOT is planning for the possibility of not having enough room for one-way traffic on the highway.
“The roadway to Cooke City [Montana] is now open for the season, so people who live in this valley have another way out of the Sunlight and Crandall areas if we lose the entire width of the highway,” he said.
Hallsten said the long-term repair of the slide “is now beyond what we could do with our maintenance crews. ... We still have not determined what it will take to stabilize the slide and repair the road.”
Hallstead said the department’s geology team is still mapping the slide to determine how big it is and what is causing it.
“We believe this could be a small failure within a giant ancient landslide,” he said.
Beers said geologists haven’t been able to do all the drilling they need to map the slide and get a better idea of how large it is.
“We are concerned that we could lose the whole road,” he said. “It’s kind of dicey at this point. We just want people to be aware that if something more happens, things could get a little rough. We’re not trying to alarm anybody, but we’re tying to be up-front and proactive with information.”
“We’re up there every day looking at it,” Beers added. “Right now, all we can do is try to keep people safe.”