Boletín de aludes

Flathead Range & Glacier NP

Flathead Avalanche Center
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Peligro de aludes

Sun
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Slabs of recent storm snow may still be sensitive Saturday. Wet loose avalanches will likely run on sunny slopes as dry snow gets wet. Both hazards will be bigger, big enough to be dangerous, the higher up you go. Test the bond at the new snow/old snow interface on small slopes before committing to steep terrain. Watch for rollerballs on sunny slopes as a sign to look for shade.

Problemas de aludes

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–3

    Since precipitation has ended, stability is improving. However, recent snow may still be sensitive to your weight. Slabs will increase in size at upper elevations. On Friday, a soft slab avalanche ran naturally, and riders reported collapsing and shooting cracks near WRM. Cautiously test the bond of the new snow to the old on small test slopes. Fresh, natural avalanches, whumpfs, and cracking should direct you to less consequential terrain. Avoiding slopes steeper than about 35 degrees, with an eye to what’s above you, is the safest way to avoid the problem.

    (3/4/2022)

    A 1000 foot wide storm slab avalanche at 5200 feet on a convex feature.

    Photo: Mark Dundas

  • Loose Wet

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

    Saturday will be beautiful. With the sun getting higher in the sky, it will be more intense as it hits dry snow on steep slopes. It will warm up rocky areas first. Confined, concave terrain will warm the most. As dry snow becomes wet on sunny slopes, watch for rollerballs and small wet sluffs originating from cliff bands and trees. Move to shady slopes for better, safer riding before you see wet snow at the surface. Plan an afternoon exit that doesn’t expose you to large, steep, sunny avalanche paths on the way out.

    (3/2/2022)

    Large wet snow avalanches on Mt. Stanton in central Glacier Park

    Photo: BJ Johnson

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    2–3

    On isolated slopes, dense avalanche debris may release slabs that break on crusts or weak snow buried well below the snow surface. Water has penetrated the snowpack to weak layers buried in January or February. Avalanches that break on or step down to those layers can be much wider, break around terrain features and into multiple start zones. Avoiding convex, complex slopes steeper than about 35 degrees is the most reliable way to reduce your exposure to this relatively isolated hazard.

    (3/3/2022)

    The top meter of the snowpack near the tail end of the substantial wet, warm storm. Rain late in the storm left wet surface conditions. Warm, dense snow earlier in the storm left moist snow. Below a crust, the snow remains dry.

    Photo: Clancy Nelson

Avalanche Discussion

With the rain finally over, people began to test the waters and venture back into the mountains on Friday. Reports of carnage from the recent storm abound. Large to very large loose wet and slab avalanches ran in many paths at all elevations. 

Also, Friday, a few large wet sluffs ran in south-facing chutes in Glacier Park. Riders in the Flathead Range reported up to 24 inches of cohesionless snow above 7000 feet. Several inches of snow fell throughout the day. A soft slab avalanche near WMR ran as the sun hit southerly aspects. Observers in Canyon Creek also noted shooting cracks and collapsing under the most recent storm snow at mid-elevations. Slabs of recent snow may still be sensitive to human triggers this weekend. It will be clearer Saturday, and the sun is getting higher and more intense as we get closer to spring. Wet loose avalanches can run naturally where the sun hits dry snow. 

Since Sunday night, we’ve received 4 to 6+ inches of water. It mainly fell as rain below about 6500 feet, which wet the snowpack down to old crusts, weak layers, and windboard from mid-February. It’s not out of the question for avalanche debris from above to break down to old, weak snow on isolated slopes.

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