Boletín de aludes

Flathead Range & Glacier NP

Flathead Avalanche Center
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Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
1 · Débil
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 8 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Today you can find more great riding than avalanche trouble. The avalanche hazards that exist are isolated to some steep, upper-elevation slopes, where you can trigger slabs of drifted snow or long-running sluffs that might be dangerous if they carry you into a terrain trap. You can avoid dealing with these hazards by sticking to wind-sheltered terrain with clean runouts.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    On steep slopes near summits and ridge crests, you may be able to trigger slabs of drifted snow. These can involve recently-formed soft slabs, or older hard slabs disguised by the most recent snow. The former will be the most sensitive to your weight; the latter will produce larger, more dangerous avalanches. 

    The most straightforward way to minimize this isolated hazard is to stick to wind-sheltered terrain, where the riding is likely best. These are mid and upper-elevation slopes without drifts, that aren't overhung by sensitive cornices, and where the snow surface remains loose rather than packed or dense. 

    If you are looking to climb or descend more commiting terrain near summits or ridgecrests, you'll have to do a slope-specific evaluation of conditions. Fresh, soft cornice? Thick, cakey feeling snow that cracks around you? Is there a thick, hard layer underlain by much softer snow? Is the runout free of terrain traps? "Yes" answers to more than one of these questions suggests a potentially dangerous wind slab exists. 

    (12/21/2025)

    The soft slabs that may still pose a hazard today will look like this - dense, cracking with your weight on test slopes. 

    Photo: Josh Lipkowitz

  • Loose Dry

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    You can trigger long-running sluffs on very steep, upper elevation slopes. These could involve enough debris to be dangerous where there's 6 inches or more of loose unconsolidated snow, or where they're above terrain traps like rocks, gullies, or trees. On continuously steep slopes where the loose snow sits on firmer old snow, triggered sluffs could run far and fast. 

    You can reduce the threat these pose by choosing lines that aren't above terrain traps, turning out of your sluff before it builds, or avoiding terrain likely to harbor this hazard. 

    (1/29/2023)

    An example of the kind of sluffs you can trigger today. These can be large enough to be dangerous on continuously steep slopes or above terrain traps.

Avalanche Discussion

Yes, Virginia, there is good riding in the mountains around the Flathead Valley. You might not think so, given the anomolously warm storms, drenching rain, and images of nightmare blowdown. However, get above about 6000 feet in wind-sheltered terrain, and you can find soft snow that makes for great turns and edging on a sled. While you can also find avalanche trouble, it's limited  to steep, leeward slopes near ridge crests and summits, and continuously steep slopes with more than about 6 inches of loose, unconsolidated recent snow. OK, so getting above 6000 feet is tougher than usual. 

If you're itching to get into steep terrain at upper elevations today, do your homework. Have a satisfying Plan B in mind, look for clues to recent wind transport as you apporach your objective, and do a slope-specific assessment of Wind Slab and Loose Dry avalanche hazards for your considered terrain. If that level of effort feels like too much in the holiday week, stick to wind-sheltered terrain that's not continuously steep.

From field reports so far, it does not appear that the region is plagued by any widespread persistent weak layer. We have one report from the Stryker Ridge area of facets above the Atmospheric River crust/ ice that produced propagation in a large column test. We did not find anything similar in a profile on a northerly, upper-elevation slope in the Skyland area Monday, though lower elevations had several crusts that have the potential for problems in the future. It's worth digging and testing if you're getting into terrain for the first time this winter; please let us know if you find anything alarming. 

 

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