This story originally said the road closure was effective immediately, based upon information from the Idaho Transportation Department. The agency later learned that information was incorrect.
A 12-mile section of the state highway above Lowman to Banner Summit will close at 4 p.m. Friday as a safety precaution, the Idaho Transportation Department said.
The route will be evaluated regularly to determine when it's safe enough to reopen, officials said.
That area of Boise County typically receives more than 250 inches of snow per year and slides, between 45 to 50 per year, are common.
The state has reduced closures by more than 60 percent since a team began forecasting slides and slide threats three years ago.
Ninety percent of the Idaho avalanches that affect highway travel occur in the "Avalanche Alley" section between the Grandjean Junction turnoff and Banner Summit. About 60 chutes where avalanches develop are found in that area.
The first closure of the season came Dec. 16.