Boletín de aludes

Snoqualmie Pass

Northwest Avalanche Center
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Peligro de aludes

Fri
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 5 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Shifting winds continue to drift low-density snow into slabs you can trigger as you ascend into exposed terrain. Textured surfaces and cornice-like features help point out slopes you want to avoid. Sluffs can quickly take away your control in areas of steep, unconsolidated snow.

Problemas de aludes

  • Wind Slabs

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

    Soft and unconsolidated snow abounds in wind-sheltered areas. A pattern of shifting wind direction at Snoqualmie Pass continues to transport the snow in more exposed terrain, forming slabs that you can trigger. Moderate easterly winds on Wednesday switch westerly Thursday, maintaining heightened danger and a variety of recent loading patterns near treeline and above. You're most likely to trigger a wind slab adjacent to a ridgeline, on an exposed slope, or where snow piles up at the base of a cliff. Actively blowing snow, fresh sharp wind drifts or cornices, and firm, punchy snow surfaces can clue you into the immediate problem. 

    Anywhere the snow remains light and fluffy, anticipate small Dry Loose avalanches that can be consequential in steep, rocky terrain.

    (12/14/2021)

    Small wind slabs triggered in steep N-facing terrain just below the ridgeline on Mt. Snoqualmie.

    Photo: Public Observation

Avalanche Discussion

Snoqualmie Pass may pick up 1-3" of fresh snowfall through Thursday. The new snow adds a fresh coat to more than 3 feet of snow that fell at Pass level in the past week, with even more at higher elevations. Settlement has created a generally right-side-up snowpack. You can still identify several storm layers within the upper snowpack. Storm slab activity has not been reported on these layers since 12/12. We continue to track a thin crust (12/8) about 4-6” above the icy block at the bottom of the snow. In nearby Stevens Pass and the West South zones, small weak facets were observed near this crust. So far, we have not confirmed any avalanches on this layer. However, if you dig in the snow, see if your snowpack tests fail suddenly or slide easily on weak grains around the crust.

The early season snowpack is relatively variable and can change by aspect, elevation, and location. The snowpack formed very recently and observations have been limited to more easily accessed locations. As you approach new terrain, small test slopes can help you gather information before stepping out into larger and less higher consequence terrain.  Also, consider giving yourself a margin of safety as you travel near smooth rock slabs such as this frequent flyer at Alpental which released to the bedrock early on 12/14.

Open creeks continue to present a barrier to backcountry travelers at lower elevations. Choose your travel routes and creek crossing carefully.

Regiones cubiertas