Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

As you gain elevation you can get caught by slabs of dense, wind-textured snow that break near ridgelines and on the sidewalls of gullies. Some may be large enough to bury you, and early season conditions mean that taking a ride through brush and over rocks is likely to injure you. Sheltered terrain with soft, incohesive snow is a safer place to enjoy the alders and logs.

Conditions will deteriorate overnight and the danger will rise into tomorrow as a powerful storm enters our area.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Southwest winds over the past few days have been at snow-blowing speeds near ridgetops. They will increase again as more snow falls by Friday afternoon. As you travel above about 6,000 feet, use caution on leeward slopes steeper than about 35 degrees. Rippled, rounded drifts that crack around you mean you’ve found slabs that are sensitive to your weight. These will be most likely below cornices on ridgelines and saddles. You may find them further down slope on the sides of chutes and gullies.

    (12/8/2021)

    Denser slabs of drifted snow are often found below cornices. 

    Photo: George

Avalanche Discussion

Riders triggered a few small avalanches during the last good burst of snow on Wednesday, and it’s been pretty quiet since. The cold air that moved in Wednesday night may have toughened slabs that were reactive during the day, making them more stubborn to riders and explosives by Thursday morning.

Moderate to strong winds continued to blow snow at upper elevations through Thursday. I was above Essex and was pretty glad I didn’t venture into exposed terrain above 7,000 feet. Snow showers and winds will pick up again through the afternoon, meaning that wind slabs could continue to grow in higher terrain.

We haven't got much of a snowpack across the region below 5,000 feet. There were only 8 inches of snow at that elevation in the Flathead Range on Thursday and less in the Swan and Whitefish Ranges. Above that elevation, a layered winter snowpack has been building. Tough crusts surround layers of weak sugary snow above the ground. Lower density snow that has fallen since December 4th covers that. A weak layer of preserved dendrites in the upper snowpack has been the cause of recent storm slab activity. A hard ice crust caps it in the Swan, but not in the Whitefish and Flathead. That layer and the deeper facet/crust combos are layers to keep in mind as an atmospheric river brings a heavy load of new snow and powerful winds starting late Friday night.

Regions covered