Bulletin d’avalanche

East Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
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

Strong sun and warming temperatures will create small loose wet avalanches on slopes that receive direct sun during the day. Start early, and plan to move off of steep slopes once you find signs of warming snow surfaces, such as rollerballs and fresh, loose avalanches. Be ready to navigate around wind-affected snow on upper elevation slopes where you may be able to trigger wind slab avalanches. 

Problèmes avalancheux

  • Loose Wet

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

    Although the day will start cold, we can expect the strong mid-April sun to quickly warm snow surfaces and set off a round of wet loose avalanches. Look for these to occur first on the east aspects and later on west-facing slopes. Plan your day to start and end early and have a contingency plan in place if avalanches start sooner than you anticipate. Feel for moistening snow surfaces and watch for indicators of warming snow surfaces, such as rollerballs. Be ready to move to shadier slopes and lower angled terrain. Avoid areas with steep overhead slopes. 

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

  • Wind Slabs

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

    Although avalanches may become more difficult to trigger they are still possible. Wind slabs could break at the new/old snow interface. Expect thicker slabs at upper elevations and on leeward slopes. You're most likely to find these below ridgelines, in gullies, and on open slopes or beneath rock bands. Feel for stiffer snow and look for wind-textured surfaces or pillows. If you notice shooting cracks or strong-over-weak layering, navigate around slopes steeper than 35 degrees nearby. 

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

Avalanche Discussion

A cold spring storm with very strong winds left around 3-5" at Washington Pass on Saturday. The new snow adds 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 a colder spell. 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 generally strong and well settled.

If you're out this weekend, help us 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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