Bulletin d’avalanche

West Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Plan for a messy and potentially dangerous Friday with a sudden shift to warmer temperatures and rain. Keep your plan and terrain choices simple so you can easily respond to changing weather conditions. If you observe heavy rainfall, then anticipate lots of natural avalanches and High avalanche danger - and avoid being on or under all steep slopes. 

Problèmes avalancheux

  • Loose Wet

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

    There is currently 3-6’ of cold, dry snow out there. It probably won’t play nice with the sharply rising temperatures and rainfall in the forecast. Wet avalanches should go from being an issue at lower elevations in the morning to all elevations by the end of the day,

    Rollerballs and pinwheels and thick, sticky snow are the first signs of warming. While loose snow avalanches are the kind you are most likely to see, also look out for sagging cornices and blocks of snow sliding off of cliffs and rock slabs. Wet slab avalanches are also possible. If you see wet avalanches, then expect to see more.

    Stay away from steep slopes as temps rise and snow turns to rain. Wet avalanches often initiate from steep treed or cliffy terrain. Keep track of what is overhead.

    (3/26/2021)

    Rollerballs are an early sign the snow is warming and becoming unstable.

    Photo: Andrew Kiefer

  • Storm Slabs

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

    While wet avalanches are probably the more dangerous ones you could run into, unstable slabs of new snow should also be out there, especially first thing in the morning. Snowfall will begin this evening and continue until it turns to rain at some point on Friday.

    The current snow surface of cold, dry snow might not be up to the task of supporting the denser snow that will fall on top of it. Simple tests like slope cuts, skin track tests, and hand shears can help you get an idea of how unstable the new slabs might be.

    (2/13/2021)

    A small snowmobile triggered storm slab.

    Photo: Jon Ferrian

Avalanche Discussion

Lots of folks around West North made good use of good snow conditions Thursday - and found little in the way of avalanche activity while they were out there. One recent natural avalanche (D1) was observed on the north side of Table Mt. and debris from a natural avalanche that released mid-storm was spotted in Glacier Creek. While wind-affected snow was easy enough to find, it was also easy to avoid. 

There is anywhere from three to six feet of snow over the melt-freeze crust buried just before the New Year on 12/30/23. While a few layer interfaces produced sizeable avalanches so far in 2024, none of the interfaces stayed reactive enough for long enough to reach problem status. That being said, pockets of weak snow with plenty of slab above still exist here and there in the forecast zone.

You can dig down to asses snowpack layering, especially in less frequently traveled locations. Whatever you do, don’t ignore obvious signs of instability like whumping, shooting cracks, or recent avalanches. When in doubt steer towards lower angled, less consequential terrain.

Régions couvertes