Traffic & Transportation

Strong snowstorm, avalanche risk will close parts of Idaho 21. Where it’s closed

The Idaho Transportation Department will close Idaho 21 north and south of Lowman on Thursday, March 9, at 6 p.m. as a major storm system brings heavy snow, high winds and avalanche danger to the region.
The Idaho Transportation Department will close Idaho 21 north and south of Lowman on Thursday, March 9, at 6 p.m. as a major storm system brings heavy snow, high winds and avalanche danger to the region. Idaho Transportation Department

The Idaho Transportation Department will close parts of Idaho 21 at 6 p.m. on Thursday as a significant winter storm plows through Idaho.

Over half-a-foot of snow is forecast to drop in Lowman, according to the National Weather Service, while 12 to 18 inches is expected in Stanley. Other areas of the Boise Mountains, such as Ketchum, could receive up to 2 feet of snow.

The highway will be closed north and south of Lowman, from milepost 93.7 to 105.5 (Grandjean to Banner Summit) north of Lowman, and from 70 to milepost 48 near Idaho City to the south.

“This storm could deliver up to 2 feet of fresh snow, and with wind gusts near 25 miles per hour,” Eric Copeland, field operations manager for the Idaho Transportation Department, said in a news release. “We are expecting next to no visibility and drifting, making it too dangerous to travel.”

ITD expects the highway sections to reopen sometime on Saturday, based on current weather forecasts.

An avalanche risk was also issued for the section of Idaho 21 between Grandjean and Banner Summit. The Sawtooth Avalanche Center warned that the avalanche risk would rise after dark, and avalanche warnings would likely be issued.

Parts of the mountains around Idaho 21, between Idaho City and Lowman, already have a snow depth of 5 to 8 feet, according to the U.S. Forest Service, before the upcoming storm.

This story was originally published March 9, 2023 at 4:37 PM.

Shaun Goodwin
Idaho Statesman
Shaun Goodwin is the Boise State Athletics reporter for the Idaho Statesman, covering Broncos football, basketball and more. If you like stories like this, please consider supporting our work with a digital subscription. Support my work with a digital subscription
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