Avalanche danger increases in North Idaho

Avalanche danger is increasing in the mountains of North Idaho with Thursday night’s snow falling on top of a crusted layer of hoar frost and light snow.

The Idaho Panhandle Avalanche Center on Friday said the risk of a snow slide will increase as a new Pacific storm arrives in the region tonight.

In response, the National Weather Service in Spokane issued an avalanche warning for Sunday and Monday for the mountains of Bonner, Boundary and Shoshone counties.

The warnings do not apply to maintained ski areas.

The weather service is predicting 5 to 17 inches of new snow tonight and Sunday in the mountains on top of the 3 to 5 inches that fell overnight Thursday and Friday. Some of the new snow was blown by the wind and should be deeper on leeward slopes, the center said.

The forecast calls for heavier amounts of snow tonight and Sunday in the mountains near Lookout Pass.

Snow changing to rain is expected at lower elevations.

The weather service Friday afternoon posted a winter weather advisory for locations north of Sandpoint and Deer Park; the east slopes of the Cascades; and areas north of Interstate 90 in the Columbia Basin for 2 to 5 inches of snow tonight before the snow changes to rain.

The avalanche center said it has found two layers of instability in the snow pack that could fail with a new snow load on top of them.

The avalanche center specifically identified the Selkirk and Cabinet mountains northwest and northeast of Sandpoint and the St. Regis Basin adjacent to the Silver Valley in Shoshone County as having moderate avalanche danger through today and increasing Sunday.

Backcountry travel should be done with caution, officials said. The center said natural avalanches are unlikely, but there is a possibility of human-triggered slides.