Boletín de aludes

East Slopes South

Northwest Avalanche Center
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Peligro de aludes

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

Lo esencial

It is likely to trigger a wet or dry snow avalanche large enough to kill you on Monday, particularly if you are closer to the Cascade Crest. Some things to look out for are rainfall lower down, blowing snow higher up, sloppy wet snow you're punching deeply through, and cracking or collapsing in dry snow. Manage the complexity by defaulting to sheltered slopes that are not steeper than 35 degrees.

Problemas de aludes

  • Wet Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1.5–2.5

    Wet slab, persistent slab, wet loose, even glide—whatever you want to call them, liquid water has been and continues to be introduced to the snowpack, elevating the likelihood of avalanches. Until water has time to drain out or refreeze, avalanches will be of concern.

    It's possible most avalanche paths where slides could grow large enough to kill you released over the weekend. However, we have very little certainty on this claim. Furthermore, new snow could accumulate in a start zone that previously released, making it hazardous again. Ultimately, we're not out of the atmospheric river yet, so with such uncertainty, enter into the mountains assuming conditions are still dangerous. Don't hang out on or below large paths if they have not slid yet. Cornices could be sagging and primed for breaking off, so be wary of precariously hanging blocks of snow above or below you. Don’t linger in terrain traps where avalanche debris can concentrate. If you find an avalanche path that has previously slid, be sure there is no lingering overhead hazard before entering it.

    (2/23/2025)

    Crown of a very large natural avalanche on the southwest side of Shukasan at about 5600'. (West North zone)

    (WS-N-D3-O)

  • Wind Slabs

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

    Sustained wind speeds up to 50 mph are forecasted overnight Sunday into Monday, accompanied by snow and dropping freezing levels. You'll likely find some new, dry snow transported by the wind. These slabs could be forming over slick crusts and an overall compromised (wetted) snowpack. So whether you find wet or dry snow problems on Monday, the likelihood of triggering an avalanche is the same.

    Wind slabs usually form just below ridgelines and on exposed convexities and gullies, but with such strong wind, look for wind-affected snow lower down on slopes than usual. New slabs could be forming in paths that just released over the weekend, making them dangerous once more. Visual clues such as cornices, blowing snow, and drifted pillow-like dunes will help you identify where the wind has transported snow. Give cornices a wide berth when standing above and below them. If you see long shooting cracks from your equipment, new slab avalanche activity, or feel collapsing, choose more sheltered and lower angle terrain.

    (2/21/2025)

    The crown of a small skier triggered slab avalanche on Blewett Pass (02/21).

    Photo: Payton Schiff

Avalanche Discussion

The timing of wet slab avalanches is nearly impossible to predict. That, combined with no new on the ground data, means we don't really know what's going on in this zone. Some things that we do have certainty about are:

  • there are known weak layers in the snowpack
  • we are still in a very active weather pattern
  • whether wet or dry, small or large, encountering an avalanche of some kind on Monday is likely
  • avalanches will be most probable the closer to the Cascade Crest you are where more new snow is forecasted to accumulate

So, if you're still reading, although we are probably past peak instability, it should be clear that we're not out of the weeds yet. As with any storm cycle, the snowpack needs time to adjust. Approach the backcountry with a healthy dose of skepticism on Monday.

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