Bollettino valanghe

Flathead Range & Glacier NP

Flathead Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 9 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

It is possible to trigger a soft slab avalanche above about 6500 feet on slopes with continuous snow cover. Shooting cracks or whumpfing collapses are signs to move to lower-angled terrain. Getting caught in a small avalanche this time of year can have significant consequences. 

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Monday and Tuesday's storm added another 3 to 8 inches of snow to the forecast zone. On many slopes with snow cover prior to the storm, the new snow fell on weak, sugary layer that developed during recent cold and clear nights. Here are a few bullet items to keep in mind during the day:

    • Shooting cracks longer than your boards or machine are a sign to move to gentler terrain.
    • Expect a slightly stiffer, possibly more sensitive slab immediately downwind of exposed ridgelines.
    • Expect sluffing if you step out onto steep slopes. These sluffs may move a surprising amount of snow. Allow sluff to move past you, not over you. 

    (11/30/2025) Nov 30, 2025: Recent crown on the east face of Goat Mtn. Photo: Seth Anderson Photo: Adam Clark

Avalanche Discussion

Observations from this weekend generally described 10 to 16 inches of recent snow above 5000 feet (Glacier National Park, Swan, Whitefish). Observers also noted weak layers of surface hoar and near-surface facets at or just below the snow surface. Avalanche activity primarily involved point releases and a couple of slab avalanches. View the Avalanche Tab for more information. Monday and Tuesday's storm deposited 3 to 8 inches of low-density snow. Thankfully, the winds dropped to single digits, reducing the amount of wind-drifted snow. 

The key to good travel right now is finding slopes with continuous snow cover. If you succeed in finding said slopes, pay close attention to signs of unstable snow. Shooting cracks and whumpfing collapses should steer you to slopes with lower angles. I mention whumpfing collapses because on many slopes, the recent snow fell on near-surface facets and/or surface hoar noted above. Slabs resting on facets and surface hoar are notorious for remote triggers or propagating wider than expected. Although triggered slab avalanches should be relatively soft, being caught in any slide right now will have big consequences. I'd test the new snow by stomping on a variety of small features with a spotter before moving onto longer slopes. 

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