Highway 21 May Open For Winter Idaho Reverses Closure Policy On Avalanche-Prone Route

The Idaho Transportation Department has reversed a policy calling for the annual winter closure of the shortest route from Boise to Stanley.

Idaho Highway 21 was closed for the first time this season Friday after four minor avalanches hit near Banner Summit, about 20 miles west of Stanley. But workers will check today to see whether the snow has stabilized with cooler weather and the route can be cleared safely - possibly by midweek.

The cost and safety concerns of closing and reopening the road after avalanches have been debated for years. Last May, the Idaho Transportation Board decided to close the avalanche-prone stretch for most of the winter.

Criticism by Boise recreationists and Stanley merchants prompted the new decision.

The Transportation Department plans to install two remote weather stations this summer and repair a third one near the road at a cost of about $30,000. That is in addition to the annual costs of about $32,500 for station maintenance, surveys by skiers and airplanes and blasting tests.

“If the road stays open, it helps our economic base, even though there are alternative ways to get here,” Stanley Mayor Bunny Danner, owner of Danner’s Log Cabin Motel, said Friday. “Our little town keeps trying to grow, and keeping the route open through the largest populated area is a real necessity.”

The alternative route to Stanley, through Sun Valley, is 214 miles from Boise, compared with 130 miles via Idaho 21.

The snowpack along the route is treacherous because the bottom layer has “freeze-dried” ice crystals, assistant Transportation Department maintenance engineer Dick Powell said. The crystals act like ball bearings, allowing the upper snow layers to slide off them.

Heavy snowfall is compounding the threat.

Friday’s avalanches did not block the steep road, Powell said, but “a car could barely get around them, and they were too high for snowplows to move.”