Bulletin d’avalanche

Snoqualmie Pass

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

You could experience radically different conditions depending on your proximity to the Pass, elevation, and time of day. Cooling temperatures and east winds will help the avalanche danger slowly drop. Even still, this is a weird weather pattern, so choose routes that let you easily adapt to the conditions.

Problèmes avalancheux

  • Loose Wet

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

    You’re most likely to encounter wet loose avalanches west of the Pass, if the sun comes out,  and if overnight temperatures at Alpental finally push above freezing. It will be a good morning to check the weather stations to see how warm it got and where. Further east, near Gold Hill and Crystal Springs, this problem could be less likely. 

    It should be easy to identify. If you find wet sticky snow, see new rollerballs, or find tear-drop-shaped slides, you’ve found the issue. Most of these avalanches should be small. However, they’ll probably be heavy and could carry you into places you don’t want to go (creeks, cliffs, trees).

    (1/4/2024)

    Example: Wet avalanches like this could occur where temperatures pop above freezing. 

    Photo: Dallas Glass

  • Wind Slabs

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

    Wind slabs won’t be everywhere, but you’ll be more likely to find them further east and near the Pass proper if temperatures stay cold. Moderate easterly flow near road level formed wind slabs even at lower elevations. 

    Look for textured surfaces, rime, and sharp drifts to point toward potentially wind-loaded features. These wind slabs could be very firm, making them harder to predict. In some cases, they might even sit over weak facets (1/16 interface), allowing them to trigger easily and possibly break above you. Give steep wind-loaded slopes a wide berth, and seek out more sheltered terrain.

    (1/14/2024)

    Textured surfaces and drifts.

    Photo: Andy Harrington

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    2–3

    With a little bit of visibility today, we didn’t hear about any new slides. That, combined with some less impressive test results, is helping us slowly decrease the likelihood of this problem. However, plenty of uncertainty remains. 

    The likelihood is dropping, but the consequences remain high. This layer is so deep, it won’t “talk to you” until the entire slope lets go. A layer of weak facets lingers 4-5ft (120-150cm) below the surface in the Soltice Crusts. Make sure to discuss this problem before committing to large slopes.

    (1/10/2024)

    This very large avalanche released using explosives during avalanche control at Alpental. It is an indication that deeply buried weak layers could still be active. 

    Photo: Alpental Ski Patrol

Avalanche Discussion

This weather pattern created quite a mess at the Pass, with variable, overlapping avalanche problems, and uncertainty on exactly how all this will play out. In some regards, the only way to know will be to go and look. The overnight weather will have a significant impact on avalanche danger and problems on Saturday. 

On Friday, NWAC forecasters and avalanche professionals at the Pass continued to find soft dry snow. A freezing rain event at mid-elevations may have left a thin ice crust in some areas. This will help minimize the avalanche danger in these locations. While the Pass stayed very cold, temperatures just a bit west hit 40F at 4500ft! Avalanche activity seemed to be limited to very shallow (4-6in) soft storm slabs on unsupported slopes.

Régions couvertes