Why does ITD close Highway 21 ...

When winter storms threaten to dump snow in Idaho's central mountains, ITD occasionally closes Idaho 21 as a precautionary measure. That sometimes prompts questions by motorists who travel the route from Banks to Lowman. "Why close the highway if there are no avalanches?" they wonder. The answers are evident in photographs.

ITD closed the highway between the Grandjean Junction and Banner Summit Wednesday (Jan. 18). The following two days, maintenance crews pondered how to clear 37 slides that covered the highway where motorists usually travel.

Precaution works.

Along with the 40 inches of snow at the summit when the route was closed, another 53 inches fell during the closure. The area also received nearly five inches of rain, making the chutes primed for major slides.

Avalanche Alley, as it's commonly called, did not disappoint.

Crews worked hard over the weekend to clear the snow, rocks and debris that plowed down steep slopes, including one (pictured above) of more than 20 feet high. Thanks to their tireless efforts and aggressive snow-eating equipment, they managed to clear the slides, enabling the route to be reopened early today (Jan. 27).


Published 1-27-2012