Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Mon
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Touchy conditions continue as more natural and human-triggered avalanches occurred on Christmas Day. It is likely that you can cause an avalanche, so avoid steep slopes as you enjoy all the new snow on Sunday.

Problèmes avalancheux

  • Wind Slabs

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

    Wind redistributed snow into reactive pockets on Christmas Day. One observer in the West North Zone, with similar conditions to the West Central Zone, reported a natural avalanche cycle where they traveled in the Near Treeline. The avalanches were mostly small, however larger ones in higher and more exposed terrain were a very real possibility. You can check out the observation HERE. Another backcountry user reported very touchy conditions, triggering avalanches 20 feet out in front of them consistently, although they were mainly only about 4 inches deep and clearly wind affected. 

    On Sunday, human triggered wind slab avalanches are likely. They will probably remain small, but it is not out of the question that they could break down to the Solstice Crust, now buried about 2 feet deep. Slabs may be subtle and soft, making it challenging to identify wind-loaded areas. Search for the usual clues such as heavier or textured snow, and shooting cracks or whumphing. Stay off these slopes or any other steep ones suspect of wind loading. If you find it at all difficult to identify which slopes are wind-loaded, stick to terrain less than 35 degrees.

    (12/23/2021)

    Cracking in the new snow indicates the snowpack is weak and could avalanche.

    Photo: Sam Luthy

  • Storm Slabs

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

    Over two feet of snow has fallen in the last 4 days. Even on non wind-loaded slopes you could encounter soft storm slabs. They could  propagate only a short distance, or they may entrain additional soft snow as they descend, acting more like a dry loose avalanche. Regardless of what you want to call them, the end result is the same. They’ll occur on slopes greater than 35 degrees, and will probably remain limited to the top few inches. There is a small chance they could break as deep as the Solstice Crust.

    Even small storm slab avalanches present a danger when combined with terrain traps.

    Photo: Lee Lazzara

Avalanche Discussion

We’ve received over two feet of snow throughout the zone since Tuesday. One last wave of snowfall will continue into Saturday night before the tap slowly squeezes shut and temperatures plummet for the next several days. This snow came in colder, drier, and lower density than what we’re used to here in the Pacific Northwest. Even if you’re only traveling to “lower elevation” areas, expect to find snow. Check out the BLOG I wrote earlier in the year about hiking and snowshoeing in the Cascades. Don’t forget to prepare for snow and cold temperatures no matter what elevation you’re getting out to on Sunday!

Régions couvertes