Boletín de aludes

Snoqualmie Pass

Northwest Avalanche Center
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Peligro de aludes

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

Lo esencial

A small storm will bring rain/snow to the Pass on Sunday. Expect avalanche hazard to build as more precipitation falls. Be leery of higher consequence slopes where these smaller avalanches could take you for a nasty ride.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    1–1.5

    Increasing winds should combine with a few inches of new snow to build a fresh crop of wind slabs throughout the course of the day. Blowing snow will help you determine local wind patterns and anticipate wind-loaded features. You can also look for textured surfaces and sharp drifts to point toward fim pillow-like slabs. In general, these avalanches should stay pretty small, but don’t let them carry you over a cliff or into rocks. 

    Some of these shallow wind slabs may form over dry weak snow that developed last week. You’re most likely to find surface hoar, facets, and/or fluffy powder on shaded slopes at middle and upper elevations. As the new snow stacks up, you may see small shooting cracks or uptrack tests that fail even in non-wind loaded terrain. If you notice this, expect wind slabs to trigger very easily, even if they’re very small.

    (2/18/2023)

    Signs of wind loading to look for Saturday.

    Photo: Dallas Glass

  • Loose Wet

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

    Near and below the rain/snow line, you could see piles of rollerballs and a few small wet loose avalanches. These will be most prominent on shaded slopes where cold, dry snow lingered through Saturday’s sunny weather. As the rain affects the upper few inches of the snowpack, it could start to slide downhill over a firm crust. This may allow slides to travel quickly and gather additional snow. These natural avalanches should stay small, but don’t let one push you into a creek or bury you in a gully. 

    On more southerly aspects, a new surface crust should help limit, but may not totally eliminate wet avalanche issues.

    (1/4/2024)

    Example: You could see small wet loose slides like this on Sunday. 

    Photo: Dallas Glass

Avalanche Discussion

Sunday’s avalanche forecast looks remarkably similar to Saturday’s but for a very different reason. This storm isn’t very big, but it should bring enough precipitation to slowly increase the avalanche hazard throughout the day. 

Saturday’s weather could impact how certain aspects respond to the rain and snow. Plenty of sunshine created a very aspect-dependent snowpack. Southerly slopes baked in the sun and will likely have a new surface crust. As mentioned above, this may limit wet loose issues and could provide a slick surface for wind slabs. Shaded slopes remained cold and dry. Since the wind never really increased on Saturday, surface hoar and near-surface facets likely survived in these areas. 

As of Saturday afternoon, about 6-8 inches (15-20cm) of recent snow sits over the very stout Early February Crust (EFC). This recent snow was generally light, unconsolidated, and right-side-up in non-sun affected terrain. The EFC continues to be very slick. 

The recent snow significantly improved travel conditions. However, open creeks, holes, and piles of avalanche debris still make common routes more challenging.

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