Bollettino valanghe

Flathead Range & Glacier NP

Flathead Avalanche Center
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Pericolo valanghe

Fri
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
2 · Moderato
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In sintesi

Very dangerous avalanche conditions exist. Extreme winds have formed sensitive, thick slabs of wind-drifted snow atop buried weak layers. Large to very large avalanches, 2 to 5+ feet deep, are likely. Stay out of avalanche terrain and away from the runouts of large paths above you.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–3

    Strong-to-extreme southwest winds, combined with snowfall, will further stress buried weak layers. Recent avalanches failing on these layers have been surprisingly wide and remotely triggered from above, below, and the sides. You may not notice signs of instability until an avalanche occurs. 

    Stay away from any steep terrain that faces NW-NE-S. Large to very large avalanches, both natural and human-triggered, have been reported almost daily before this most recent loading. Give avalanche terrain a wide berth today as the snowpack receives a significant amount of weight from the recent snow.

    Recent wind-drifted snow will serve to exacerbate the destructive force of an avalanche failing on a variety of weak layers. Steer clear of steep terrain that faces NW-NE-S.

    (2/16/2026)

    The crown of a large (D2) avalanche. This avalanche failed on a ENE aspect at 6250 feet. 

    Photo: Cam Johnson

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1–2.5

    Extreme southwest winds have formed sensitive slabs of wind-drifted snow. Expect to find this problem on slopes that generally face NW-N-SE. Slab depth will increase markedly with elevation and directly below terrain features such as ridgelines, saddles, and cliff bands. 

    Shooting cracks beneath you are a sign of being on unstable snow. Move to protected terrain, where you find untextured, unconsolidated snow. Be aware that if steered towards sheltered terrain, you may trigger loose dry sluffs involving the recent snow on steep slopes. The safest slope right now is gentle in angle, disconnected from steep terrain, and shielded from the wind.

    Areas directly below ridgelines and cross-loaded mid-slope areas are likely spots to encounter sensitive wind slabs. Avoid areas with wind effects and seek out sheltered slopes for better, safer snow.

     

    (12/8/2025)

    We approached this test slope and triggered a slab that would have slid if it weren't short and concave. Cracks traveled approximately 50 feet and traveled far back onto the flat ridge line. 

     

    Photo: Flathead Avalanche Center

Avalanche Discussion

With each snowpack-loading event over the last month, we have witnessed a round of natural and human-triggered avalanches. Based on this past pattern, today’s (Thursday) sensitivity is expected to increase. 

It’s hard to quantify recent snowfall amounts when winds are blowing in the twenties and gusting in the sixties. Before the storm, however, there was ample snow for transport, and snowfall has certainly accompanied the winds of the present. Thickening and stiffening of the slab on leeward aspects is all but guaranteed today, the same slopes that harbor the Persistent Slab problem.

A well-documented crust from last weekend's warm weather is present on all aspects up to about 6,500 feet.  Above there, the crust thins on shaded aspects. These same aspects, with a thin-to-nonexistent crust, have now experienced significant wind loading. Combine the lack of a crust with recently drifted snow, and we have a thicker slab over a proven sensitive weak layer. A blueprint for large, destructive avalanches.

Travel advice for today remains simple. Steer clear of avalanche terrain; even nibbling at the edges of a slope is likely a dangerous endeavor.

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