Bulletin d’avalanche

East Slopes North

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

New snow with very strong winds may create heightened avalanche conditions at upper elevations. Identify and steer around slopes of increased consequences if you find signs of instability such as shooting cracks, and strong over weak layering. Small wet loose avalanches could be triggered at lower elevations with daytime warming.

Problèmes avalancheux

  • Wind Slabs

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

    Strong westerly winds will quickly transport the fresh low-density snow into thicker slabs at upper elevations. Monitor the amount of new snow over recent crusts as you travel. You are most likely to find these below ridgelines, in gullies, and on open slopes or beneath rock bands. Expect thicker slabs at upper elevations on leeward slopes (north to east to south). Slabs may break at the new snow/old snow interface, but above treeline and in prime loading locations they could step down to older layers and up to about 1.5ft deep. Feel for stiffer snow and identify wind-textured surfaces or pillows of fresh snow. If you notice shooting cracks or any fresh avalanches, stay off slopes greater than 35 degrees.

    (3/20/2021) Example: Using visual clues is a great way to help identify the potential for Wind Slabs.

  • Loose Wet

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

    Saturday looks like a cold and breezy day, but it's nearly mid-April, so expect some warming of snow surfaces. Loose wet avalanches could be triggered on slopes that receive direct sun. Feel for moistening snow surfaces, and watch for indicators of snow surfaces losing strength such as rollerballs. If this starts happening move to shadier slopes or lower angle terrain without steeper slopes above you. 

    (4/9/2021) Example small wet loose avalanches from near Stevens Pass.

Avalanche Discussion

A cold spring storm with very strong winds looks to roll through on Friday night. Cold temperatures and strong wind will easily transport the new snow (3"-8") into drifts and slabs. 

The new snow will be adding to the 3-6" of new snow that fell over the 4/7 interface. On sunny aspects, a firm crust marks that layer. In shadier terrain, you may find a variety of surfaces at the same depth.  The cold temperatures will help limit, but won't eliminate the potential for cornice and glide avalanches. These difficult to predict spring events can still fail even during these colder spells. Choose routes that help you limit the amount of time you need to spend below looming cornices and crevasse-like glide cracks. The lower snowpack is strong and well settled.

If you're out this weekend, help us and the rest of the backcountry community keep up with the quickly changing spring conditions by submitting an observation here. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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