Boletín de aludes

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Peligro de aludes

Sat
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Triggering an avalanche large enough to bury a person is likely, especially in areas where wind has stiffened the snow surface or built thick drifts. Build in a wide safety margin. You could trigger avalanches remotely—from flat terrain below, above, and to the sides of steep slopes.

Problemas de aludes

  • Wind Slabs

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

    Your odds of triggering a large wind slab avalanche increase as you climb into windier terrain at upper elevations. This problem is more pronounced in the Smoky Mountains, where more snow has fallen. Wind speeds will increase this afternoon, moving snow into sensitive drifts. Avalanches may release naturally and will be easy to trigger. These slides can potentially step down into the buried weak layers described in Problem #2 below. 

    Wind slabs often form near ridgelines or along steep mid-slope gullies. You can reduce your chances of triggering a wind slab by looking for and avoiding slopes with obvious signs of wind-loading, such as new cornice growth and large dunes or pillows of wind-blown snow.

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1.5–2

    Triggering a large persistent slab avalanche is likely. Yesterday, near Banner Summit, we triggered small slabs at middle elevations. Similar slabs exist in this zone. They will be thicker and easier to trigger in areas where you find drifts or a stiff snow surface.

    Various weak layers of snow (facets, crust-facet combinations, and possibly surface hoar) exist on most slopes. Ongoing storms stress these layers and increase the odds of triggering a persistent slab avalanche at all elevations. 

    You can avoid steep slopes and obviously wind-loaded terrain to reduce your chances of triggering an avalanche. Snowpack cracking, collapsing, or whumfing are clear signs of unstable conditions. Keep a close eye on your partner and the terrain above you. Persistent Slabs can release in surprising ways, break wider than expected, and release above or hundreds of feet away from where they are triggered.

    (12/21/2024) Skier-triggered avalanche near 9800' on a NE aspect in the northern Boulder Mtns.

Avalanche Discussion

It's Day 2 of a multi-day atmospheric river event bringing heavy snowfall to the region through Sunday. Yesterday's snow totals reached 3-12", and an additional 5-7" are expected today. The wind is forming new, sensitive drifts at upper elevations, and storm snow is adding to a slab above various buried weak layers. Finding a safe place to play is becoming increasingly difficult. Avoiding obviously wind-loaded slopes is a good start. Still, the weight of storm snow alone adds significant stress to the fragile weak layers at middle and lower elevations, increasing your odds of triggering a slab avalanche on many steep slopes. 

As complexity increases, we have a narrowing margin for error. There is great skiing and riding to be had, but don't let your guard down. Several slopes are nearing their breaking point. The safest move is to keep your slope angles low and to stay out from under steep slopes.

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