Boletín de aludes

East Slopes North

Northwest Avalanche Center
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Peligro de aludes

Wed
Alta montaña
4 · Fuerte
Límite del bosque
3 · Notable
Bajo el límite
3 · Notable
Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

7a Update- Less overnight snow than forecasted. Heavy snow and wind will create large avalanches, especially at upper elevations. Use extra caution on all slopes over 35 degrees and avoid steep slopes where the wind drifts the new snow into deeper slabs. Even in wind-sheltered terrain, it may be easy to trigger dangerous avalanches in the new snow.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Very Likely
    Tamaño
    2–2.5

    Avoid traveling in or under wind-loaded avalanche terrain. The most dangerous areas will be leeward sides of ridges and wind-exposed features 35 degrees and steeper. Avalanches in these areas could be deep and large. Look for plumes of blowing snow to indicate where the wind is forming fresh slabs. The easiest way to stay safe is to stick to slopes under 35 degrees. If you see recent avalanches or cracks shooting through the snow stay on well-protected, low-angle slopes.

    (1/17/2023)

    An example of natural wind slab avalanches near the base of a cliff. 

    Photo: Katie Warren

  • Storm Slabs

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

    Even at lower elevations, it's critical that you carefully assess the new snow as you move through the mountains. Expect that it may be easy to trigger avalanches on any slopes over 35 degrees. You may find stiffer snow over softer snow as an indicator that you can trigger storm slab avalanches. Use safe and smaller test slopes to check how easily the snow slides. Making many quick tests as you move through the terrain can help you assess the chances of triggering an avalanche. Take some time to dig down about 2 feet to look at the interface that was buried at the beginning of this storm, on Friday. If you find sudden or propagating test results on older, weak snow, stick to lower-angled slopes.

    (1/9/2023)

    An example of a shallow storm slab beneath a rock outcrop.

    Photo: Willie Webster

Avalanche Discussion

On Sunday, I went to Rainy Pass and found about 1 foot of snow that accumulated since Feb 3rd. The new snow was relatively well-bonded, tho in a few places we were able to find clean shears at the new/old interface and trigger shallow point releases on steep north aspects in the new snow. We saw no other signs of instability. 

There are a few weak layers that we've been tracking in the upper snowpack. The Jan 5th surface hoar (about 2-2.5ft below the surface) has been the most widespread and problematic in snowpack tests. At a profile on Sunday near above Rainy Lake, test results indicated that the layer was not a problem for avalanches at that location. Elsewhere, especially in the eastern mountains, this layer could still be an issue if it gets stressed with the weight of enough new snow.

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