Bulletin d’avalanche

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Danger d’avalanche

Tue
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré last year. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Triggering an avalanche is very likely in areas where the wind has built fresh slabs and on steeper slopes. Avalanches may break in unexpected ways and wider than expected. Choosing simple terrain that is not connected to suspect slopes is a great way to stack the odds in your favor.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1.5–2.5

    Avalanches will be easy to trigger in wind-loaded terrain and may break wider than you expect. You'll find slabs near and below ridgelines, on the sides of cross-loaded gullies, and on aprons beneath chutes. The wind slabs will be most widespread at upper elevations, but may exist in middle elevation terrain. Wind-drifted snow will feel stiff and may keep you on the surface. Watch for dunes, drifts, and snow pillows and listen for hollow, drum-like sounding surfaces. Cracks shooting out from your skis or boards are a clear sign you've found a wind slab.

    On the northern half of the compass, the storm snow buried a variety of persistent weak layers. Freshly formed slabs are expected to be more reactive on these slopes. You may be able to remotely trigger an avalanche from lower-angle terrain above, below, or to the side of steep slopes.

    (3/15/2025) Small intentionally-triggered wind slab avalanche at 8200' on a N aspect. This broke at the new snow/old snow boundary ~10" down and was in cross-loaded terrain.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    In areas more sheltered from the wind, you may be able to trigger softer slabs and loose snow avalanches, primarily on slopes steeper than about 35 degrees. The storm snow sits atop facets, facet + crust combinations, and crusts, depending on aspect and elevation. Slabs and sluffs will be easier to trigger in some areas than others, and the differences in stability between aspects may not be easy to recognize. 

    A kiss of wind or temperature-driven density changes have consolidated the storm snow into a slab in many locations. Although smaller than the thicker wind slabs described above, this problem could be tricky to manage. Slabs may release in surprising ways and break wider than expected. They may be triggered from a distance—above, below, or to the sides of steep slopes.

    Triggered slides of any form may quickly gain mass and speed as they move downslope on hard crusts.

    (3/16/2025) Storm slabs were easy to isolate in the Basin Butte area.Photo: Sawtooth Avalanche Center

Avalanche Discussion

The final wallop of the recent storm landed over the past 24 hours, with a foot or two of fresh snow falling across the forecast region. Winds were cranking throughout the storm, and temperatures crept up to around freezing by nightfall yesterday. All this points to a widespread distribution of freshly formed slabs in middle and upper elevations in throughout forecast zones. The snowfall and winds began to back off early this morning, finally giving the snowpack a chance to rest and begin adjusting to its new load. It will be hard to predict which slopes are stabilizing more quickly today, so build a wide safety margin to handle the uncertainty.

In recent days, we've seen and received reports of some remotely triggered avalanches and long-running cracks and collapses, signs the recently buried facets and crust + facet combinations are not quickly adjusting to the new load above them. This storm may cause the weak snow beneath to misbehave, or it could be a short-lived instability; the safe move is to treat the recent observations as foreshadowing until proven otherwise. Slopes with stout crusts below the storm snow and lacking an obvious slab will offer the safest access to powder riding today. If you sense a slab in any form, avoid avalanche terrain. Be extra wary of locations with thin crusts or where no crust is discernable below the storm snow - these slopes will be the most unpredictable.

Régions couvertes