Official: Water caused the Teton Pass landslide, not an earthquake

JACKSON, Wyo. (KIFI) - There has been speculation online about earthquakes playing a role in the collapse of the Teton Pass. Highway officials say the hypothesis does not seem likely.

There were no significant earthquakes in the area in the last two weeks according to a recent seismic activity map.

The Wyoming Department of Transportation suspects the landslide was caused by water.

"There's always been a small creek at the base of the slide, the base of this little slope and really is the native material that had gotten saturated,” said Bob Hammond, Engineer with WYDOT. “It was a reddish type of silt material versus some decently graded backfill that got on top of it over the years. I suspect some spring water had got through and found different paths over the years and it got really underneath where it needed to be. That was then the springs were at the base and that water there was the large factor that changed things."  

The Teton Pass collapsed on Saturday, forcing the highway to close. On Thursday, June 6, authorities noticed large cracks appearing in the asphalt. They closed the highway to make repairs and assess the situation. The road opened later that evening. Then, on Friday, a mudslide at milepost 15 blocked the road.

Engineers are now considering creating a detour around the collapsed area. They hope to have the detour ready in weeks, not months.