BOISE -- The Idaho Transportation Department has closed Highway 21 from Grandjean Junction to Banner Summit due to possible avalanche conditions in the 12-mile stretch of roadway.
Additional snowfall is anticipated in the area today, and ITD's Avalanche Forecast Office has determined to close the roadway as a preventative measure until conditions improve enough to allow safe re-opening of the highway.
The area, from milepost 93.8-105.4, is known as Avalanche Alley, and is home to 57 known avalanche slide paths. Ninety-nine percent of Idaho's avalanches occur between Lowman and Stanley. The highway is closed an average of 60 days per year due to unstable conditions which can lead to avalanches.
During the closure, U.S.12 (Lolo Pass) will be the nearest alternate for travelers from Salmon, Challis or Montana, and motorists may also choose to go to Ketchum and take U.S. 20/26 through Fairfield and connect with I-84 at Mountain Home.
