Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Tue
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Out of date — this forecast expired 6 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Very dangerous avalanche conditions will develop today as a potent storm hits our already weak snowpack with a one-two punch of drifted and new snow. Large to very large avalanches breaking two to four feet are likely. Stay out of - and far away from - avalanche terrain today.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    Accumulating snow will only increase the chances for very large natural or remotely-triggered slabs that break two to four feet deep and across hundreds of feet. The past week has seen at least seven reported near-misses or accidents involving slabs like this, that break on weak snow buried at the end of January or in mid February. Don't add to the tally. Keep what might seem like a ridiculous distance from avalanche terrain today.

    The debris from avalanches involving these slabs could run full path, from upper elevations to valley floors. Be very sure you're not in the runout of start zones well above you.

    (2/21/2026)

    A rider sits at the crown of a large (D2.5) remotely-triggered slab. The avalanche failed on the January Drought Layer (surface hoar sitting on a crust). 

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    Steep slopes with dense drifts of wind-blown snow will grow increasingly hazardous today. Slabs six to 18 inches thick will be sensitive to the weight of a rider or snowmachine. You may find these well below ridgelines, cross-loaded into gullies, and around prominent terrain features. They'll likely feel distinctly harder than snow on sheltered slopes; shooting cracks will also give them away. 

    Keep in mind that today's winds will load the same aspects where dangerous persistent weak layers exist. So while slabs of drifted snow pose a hazard in themselves, the more significant threat is how they'll increase the likelihood of avalanches that break well below the snow surface and involve very dangerous amounts of debris that run long distances.

    Persoanlly, I wouldn't travel below steep, leeward start zones today even if they're thousands of feet above me. 

    Today's winds will be drifting snow at ridgelines, with leeward slopes (left in this image) being rapidly loaded. 

    Photo: Guy Zoellner

Avalanche Discussion

"you don't need a weatherman to know which way the wind blows" - Bob Dylan

And you don't need to be much of an avalanche forecaster to recognize that the avalanche danger will rise today. First, strong winds will drift snow at upper elevations, then accumulating snow will load persistent weak layers buried 15 to 30 inches below the snow surface. The leeward slopes (northwest through northeast to southeast), where the wind loading will be most intense, are the same shady slopes where the buried weak layers have produced numerous large to very large avalanches and multiple accidents in the past week. A one-two punch.

A weak layer also appears to exist on southerly slopes, at least in the Whitefish Range. We don't have enough data to say whether it exists elsewhere. It's a thin layer of facets and buried surface hoar right above the hard crust that formed in mid-February. It may have been the failure layer for a near miss in the southern Whitefish Range Friday, and an accident on the west side of the Whitefish Range Saturday that left a snowmobiler almost fully buried.

So the likelihood of natural and human-triggered avalanches will rise today. Avalanches involving the new and drifted snow are likely to very likely. More importantly, avalanches that step down to the buried weak layers are also likely to very likely. These may have crowns hundreds to more than a thousand feet wide, and run full path to valley floors. The number of remotely-triggered avalanches this past week is alarming; that potential will only grow today.

The terrain where you could ride without exposure to avalanche hazard was narrow before this storm, and it will shrink to almost nothing as the storm develops. Trying to outsmart or time today's growing danger may lead you into trouble. Stay off of, out from under, and far away from avalanche terrain today.

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