BOISE COUNTY, Idaho — Editor's note: The video posted in this story is from March 2019, looking at why "avalanche alley" is so dangerous, and what Idaho Transportation Department crews do to clear the road when avalanches or avalanche danger shuts it down.
Idaho Highway 21 is closed in both directions between the Grandjean junction and Banner Summit because of avalanche danger, the Idaho Transportation Department reported Thursday.
ITD plans to reassess the danger at 7 a.m. Friday, but the road is currently closed until further notice.
The affected area is between the towns of Lowman and Stanley, 23 to 35 miles from Stanley if heading toward Lowman, Idaho City or Boise on Highway 21.
This stretch of highway, nicknamed "Avalanche Alley," closes several times each winter because of avalanche risk or actual avalanches. About 60 avalanche pathways are located in the area, and those pathways cause about 90% of avalanches that affect highways in Idaho.
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