Blaine/Custer County Line
ID-21 South - Avalanche Area
Entering Avalanche Zone on ID-21 south. This area south of Banner Summit has frequent avalanches in the winter, which causes road closures.
ID-21 - Entering Boise County
Entering Boise County along ID-21 south. The Boise-Custer County Line is located on Banner Summit - Elevation 7037 Feet.