Whitefish Range

A small amount of new snow and light northeast winds will create dust on crust, or small wind slabs here and there. Exercise normal caution and good backcountry travel techniques. Only expose one person at a time, and watch for isolated steep slopes with more than 8 inches of drifted snow.

A weak arctic cold front seeps over the Divide bringing gusty northeast winds and up to 5 inches of new snow to the Swan Range and Glacier Park Tuesday. New and drifted snow will land on crusts and wind-hardened surfaces. Northeast winds tend to develop slabs in unusual places. In sheltered areas, small slabs may form over surface hoar and near surface facets. That could make them more reactive and less predictable.

The middle of the snowpack is generally settled and strong after the last week of warmer temperatures. A few layers of buried faceted grains have failed sporadically in test results over the past week. The primary layer of concern is a crust/facet combination near the base of the snowpack that was buried in early December. We’ve seen that layer in all three forecast zones, on all aspects above about 6000 feet. 

On Sunday and Monday, forecasters observed 4 very large avalanches in the Flathead Range (Observation 1, Observation 2). Those slides initiated in steep, rocky, northerly terrain above 7000 feet. They likely failed on the early December crust/facet layer near the ground. They ran during the last major storms on the 7th and 12th. Since then, no real accumulation has loaded the snowpack and a stout crust has developed across the surface. It’s unlikely that we’ll see major avalanches as a result of that deep structure until the next major loading or warming event. Though I will be eyeing alpine starting zones with thin, variable snow cover with caution until then.