Boletín de aludes

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Peligro de aludes

Sun
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

You're likely to trigger avalanches on wind loaded slopes. Loose snow avalanches are possible today on sunny slopes. Smaller avalanches may provide sufficient triggers for much larger, more destructive avalanches. Slides can be triggered 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

    You're likely to trigger wind slab avalanches in steep, wind-loaded terrain. These slides can be large on their own, but also provide an effective trigger for a much larger persistent slab avalanche, as described below. This problem is most prominent as you move up in elevation in open, wind-exposed terrain. Be on the lookout for wind affected surfaces, such as a pillowed or drifted appearance, and hollow "drum-like" slabs. Cracks shooting from your skis or sled mean you've found a sensitive slab.

    Additional Discussion: Be on the lookout for small natural and easily triggerable Wet Loose avalanches if the skies remain clear and winds are calm today. These will primarily be found in steep solar slopes and can occur near the base of rock outcrops where additional warming occurs.

    (2/6/2025) E aspect, Sun Peak

  • Persistent Slabs

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

    Triggering a very large persistent slab avalanche remains a concern. You're most likely to trigger one of these slides in steep terrain facing W-NW-N-NE-SE terrain (plot). These hefty 3-6 foot thick slabs rest above weak snow formed during January's drought, including surface hoar, facets, and facet + crust combinations.

    Although recent observations point towards an improving persistent slab problem, yesterday's snow and wind stalled the incremental progress. Wind slab avalanches and cornice failures could provide effective triggers for these deeper, more stubborn avalanches, resulting in wide and destructive slides. Snowpack collapsing or whumpfing is a clear sign of unstable conditions. However, a lack of obvious warning signs doesn't mean you're in the clear. Persistent Slabs can release in surprising ways, break wider than expected, and release above or hundreds of feet away from where they are triggered.

    (2/6/2025) A large natural persistent slab avalanche in upper Cabin Creek.

    Photo: Ben VandenBos

Avalanche Discussion

After a week-long storm cycle, we're wading into tricky waters with the combination of powder fever and limited amounts of instability feedback. Avoiding the wind slab problem should be relatively straight-forward, but the persistent slab problem requires a bit more patience and diligence. In the last couple of days, we have received reports of a few booming collapses and a couple of fresh persistent slab avalanches despite the apparent positive trend in stability.

We still have considerable amounts of uncertainty regarding the sensitivity of the persistent slab problem. Additionally, the 3-6 feet of snow (4-6 inches of water) that fell over the past week means that these persistent slab avalanches will be large and destructive. The nebulous reactivity paired with obvious high-consequences is what's keeping our terrain choices simple and conservative for the time being.

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