A mudslide has forced the Idaho Transportation Department to close an 11-mile section of Highway 21 between Grandjean and Banner Summit, with the blockage expected to keep the road shut for roughly a week depending on weather conditions.
What Happened and Where
The slide came down shortly after 6:00 p.m. Wednesday, blocking travel in both directions between milepost 94 and milepost 105. Crews reached the scene the following morning to assess the damage, and heavy equipment has since been dispatched to begin clearing the debris.
The Idaho Transportation Department cautioned that additional rainfall in the forecast could complicate and extend recovery efforts. “With more rain in the forecast, we expect the highway could remain closed for about a week,” department officials said in a public statement. “Though we are hopeful crews can reopen it sooner.”
What Drivers Should Know
Motorists planning to travel through that corridor are advised to seek alternate routes while crews work to reopen the road. Up-to-date traffic and closure information is available through Idaho 511, the state’s official traveler information service.
Highway 21, which connects the Boise area to the Sawtooth Valley and Stanley Basin, is a critical corridor for summer recreation traffic, making the timing of the closure particularly disruptive for Treasure Valley residents planning mountain travel. Those heading toward the Grandjean area or beyond should plan accordingly and monitor road conditions before departing.
The Idaho Transportation Department has not released a specific reopening date, citing the uncertainty posed by continuing wet weather in the region.