Bulletin d’avalanche

West Slopes North

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

Prepare for stormy conditions with snowfall, strong winds, and poor visibility. Avalanche danger should increase throughout the day. Avoid traveling on or directly under big steep slopes during the peak of the storm or if you see natural or human-triggered avalanches. 

Problèmes avalancheux

  • Storm Slabs

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

    A spring storm will put down up to 12” of new snow at upper elevations. Strong winds will drift the new snow and pile it on leeward slopes. You are more likely to trigger a slab in terrain with active or recent wind-loading, but warming temperatures and rising snow levels mean you could find dense, unstable slabs on any slope, wind-loaded or not.

    Pay attention to storm intensity throughout the day and track variations in snow depth and stiffness as you gain elevation and change aspects. Simple tests like slope cuts and hand shears can help you gauge slab reactivity. But stormy conditions might keep you out of most avalanche terrain no matter what you find.

    (2/17/2021)

    You are more likely to trigger a slab near convex terrain features, especially in places where wind-drifted snow accumulates.

    Photo: NWAC Observation

  • Loose Wet

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

    Warm, wet snow at low and mid-elevations will open the door to fresh wet loose avalanches running in new and older layers of snow. The likelihood will increase where snowfall switches over to rain. Rollerballs and small wet loose avalanches are signs you could see more  - or bigger - avalanches. Use caution on steep slopes with wet, mushy snow, as you can likely get some snow moving with you down the hill if you push hard enough. While some low-elevation terrain does not have the consistent snow cover to allow for avalanches, enough places do have it that it should still be on your radar.

    (2/21/2024)

    Look out for wet loose avalanches initiating in steep, rocky terrain as snow accumulates and temperatures rise.

    Photo: Zack McGill - Cascade Mountain Ascents

Avalanche Discussion

Monday and Tuesday have been quiet after a flurry of observations over the weekend. No new avalanches - or even observations - were reported in the past few days. Weather stations around the forecast zone picked up another 0.2-0.4" of precipitation with 4" of wet new snow in the Baker BC at 5000'. Winds were mostly light in the past 24 hours, but that will surely change by Wednesday morning. 

Be ready for rapid changes in weather and snow stability as we head into the heart of spring. Strong storms can give way to sun and microwave-like warming in a matter of minutes - and then turn back to snow showers by the afternoon. Dry snow avalanche problems can quickly turn into wet snow avalanche problems, or you might see both at the same time on slopes with different aspects. Low elevations have less snow than average after repeated rain and warming events throughout the winter. On the other hand, some are venturing into less traveled areas by capitalizing on easy access that is more on par with April or May.

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