Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Wed
Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Highlights

Up to 5 inches of new snow and blustery northeast winds may build small, fresh drifts in unusual locations. Watch for blowing snow creating rounded, textured slabs downwind of ridges and rollovers. They’ll deserve more caution on slopes above terrain traps and if we get more new snow than expected.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    On isolated slopes you may find fresh slabs large enough to make you think twice. Where more than 4 or 5 inches of snow accumulates, and where northeast winds are more sustained, drifts may be large enough to get you in trouble over terrain traps like gullies or cliffs. They may be more reactive if they form over layers of weak facets and surface hoar. Slick crusts may allow them to slide far down the slope. Track blowing snow and watch for cracking in pillowy drifts on unusual aspects. If you find an area where they’re more than 8 inches deep, look for sheltered slopes to ride.

    (1/15/2022)

    Wind slab triggered by cornice fall. Isolated features to steer around during times of low danger. 

    Photo: Mark Dundas

Avalanche Discussion

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.

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