Bulletin d’avalanche

Flathead Range & Glacier NP

Flathead Avalanche Center
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Danger d’avalanche

Sun
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 5 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Falling cornice and small wet slides can trigger destructive avalanches on buried weak layers. Stay well back from steep slopes sporting large, overhanging cornices. Choose routes that are not peppered with rocks to avoid triggering an avalanche from a thin spot. 

 

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3

    Loading and wetting of buried weak layers produced a natural cycle of large avalanches during last week's warming and rainfall. The January Drought Layer (JDL) has recently been found 3 to 5 feet deep and may remain intact on upper-elevation slopes that were not hammered by rain. Stout surface crusts can make triggering less likely, though these may be in short supply after little to no refreeze last night.

    Riders can more easily trigger large avalanches where weak layers are closest to the surface (i.e., rocky or wind-raked slopes). Elsewhere, falling cornice and small surface slides can still apply sufficient force to initiate a fracture. The resulting avalanche could break thousands of feet wide and would be unsurvivable. 

    (3/27/2026)

    Steep and rocky alpine slopes with cornice overhead? No thank you! That's where riders, falling chunks of snow, or surface slides are most likely to trigger a destructive avalanche. 

    Photo: Josh Lipkowitz

Avalanche Discussion

Sites at 6500 to 7500 feet are starting at or above freezing this morning, roughly 20 degrees warmer than this time yesterday. This head start makes it more likely you will encounter wet snow and weakened cornices. Some increasing cloud cover and southwest winds may limit the extent of warming/wetting/weakening on solar and windward slopes.

At the same time, cloud cover can produce a greenhouse effect on shaded slopes. If these slopes are harboring any dry snow, we could see a small wet loose avalanche cycle with step-down potential for buried weak layers. Forecasting cloud cover and water infiltration is fickle at best. Be prepared to bag it early if you start wallowing in wet snow.  

Observations from yesterday (Friday) noted little to no wet loose activity and corn (or corn-adjacent) riding. Josh visited Marion Lake, where he noted meltwater pooling roughly 2 feet deep (3/9 interface). He also reported a slew of large avalanches that occurred during the last week or so. 

 

 

Régions couvertes