Bulletin d’avalanche

West Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

It is possible for you to trigger avalanches in wind drifted deposits of snow on Thursday. Pay attention as you travel, identifying areas where you see wind-featured snow surfaces or feel firmer snow beneath you, and avoid steep slopes when you find these characteristics. Snow softening in the sun is an ongoing springtime concern, and if the sun shines on steep southerly slopes stay alert for wet snow avalanches coming down.  

Problèmes avalancheux

  • Wind Slabs

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

    Wind slabs you might encounter on Thursday are different from the ones you oftentimes see. Unusual wind directions shifted snow into areas that don't normally collect deposits.  Many recent avalanches were reported as being soft slabs. Subtle drifting still formed slabs that were reactive to a human trigger, although the slabs weren't harder like we oftentimes think of when wind slabs are the problem. They might be more difficult to identify.

    Pay attention to changes in snow texture and depth as you gain elevation and change aspects. These changes could happen quickly, where you might find major differences in only a matter of a couple feet. Signs of recent wind-effect like scoured snow surfaces and drifting behind features are good indicators of where you might encounter additional deposits. Hand pits and test slopes can help you gauge the bond of wind slabs, but don't ignore obvious signs of instability like whumphs, shooting cracks, and recent avalanches.  If you encounter these signs of instability or see clues of drifting, avoid steep nearby slopes. 

    (4/11/2022) Although this small avalanche is from another zone, avalanches throughout the Cascades have been unusual lately, breaking on small wind-drifted features in areas you don't often see wind loading due to the out-of the ordinary winds. Photo: Dallas Glass

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Freezing levels are only expected to rise to 2500 feet Thursday afternoon, but sunny skies are forecasted through much of the morning. It doesn't take much for the intense spring sun to soften steep slopes and for small wet loose avalanches to begin running down. A backcountry user reported that south-facing slopes "got fried" on Wednesday, so very early in the day you'll probably find crusts on southerly aspects. There might be enough sun to melt that crust, and send more wet loose avalanches down. Conditions quickly change, so continuously evaluate your surroundings. If you notice sunny slopes beginning to shed rollerballs and small wet loose avalanches, steer around them and the area beneath the steep slopes as well. 

    (3/13/2022)

    Small wet loose, or point release, avalanches might come down if the sun shines on Thursday. 

    Photo: Alyssa Young

Avalanche Discussion

Backcountry users reported finding low-density powder snow on Wednesday on slopes that weren't south-facing. The only avalanches they triggered were small loose dry avalanches (sluffs). This may be the case in many areas, but there's 1-2 or more feet of low-density snow coating the April 8 crust throughout the zone.  Wind redistributed the surface snow in some areas, especially along ridgelines and at higher elevations. Don't let your guard down if your day has only consisted of stable powder so far. 

As springtime progresses we begin to see fewer observations in the database, making forecasting more challenging. If you make it out into the backcountry, submit observations HERE, so that we can continue to provide you with relevant, up-to-date backcountry conditions. 

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