Bulletin d’avalanche

West Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 6 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

You are likely to trigger a large and dangerous avalanche as the largest avalanche cycle of the season continues.  Stresses a snowpack that has produced widespread human-triggered and natural avalanche activity for multiple days, with recent crown depths up to 3 ft. Keep it simple and avoid all slopes steeper than 35 degrees.

Problèmes avalancheux

  • Storm Slabs

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

    Saturday's avalanche danger is not to be taken lightly in the West North zone. Intense snowfall rates (12"+ in 24 hours) along with wind-loading will create widespread instability Friday night that we expect to produce widespread human-triggered avalanches on Saturday within the storm snow or at the new/old storm interface. Several other old snow interfaces (12/18 and 12/16) were reactive on Wednesday may remain reactive another day, given additional loading.  Failures are happening all the way down to the 12/9 crust, which should be down 4 ft by Saturday. Triggering any of these layers could produce a large avalanche. Keep it simple and stay off slopes steeper than 35 degrees while avalanches and snowfall continue.  Cracking of the snow surface, whumphing, and natural avalanche activity are all great reminders in the field to dial it back.

    Recent avalanche activity produced crowns up to 3 ft deep.  On Wednesday, a skier triggered and was partially buried in an avalanche outside the Mt Baker Ski Area boundary and other reports are trickling in. While we think that older weaker snow above the crust and recent storm layers are showing signs of healing, this weekend is not the time to test that theory. We don't know how much avalanche activity occurred Friday, but small avalanches were triggered easily by skiers and some released naturally due to intense wind loading (40 mph sustained winds) on Friday. Our storm slabs include wind slab in many areas and a persistent slab problem above the 12/9 crust. The complexity of the setup warrants patience and a conservative mindset.

    A snowboarder triggered this avalanche in the West North zone on Wednesday.

Avalanche Discussion

While conditions will be dangerous on Saturday, they are likely to become very dangerous right after the sun sets on Saturday and you should not consider lingering in avalanche terrain after dark.

We're coming into our final days of one of the largest storm cycles we’ve seen this year, and slopes may just need that little bit more snow, or a human trigger to tip the scale and avalanche. 

By Saturday morning, 4 ft of snow will have fallen in the last 5 days, so tree well/snow immersion suffocation accidents are a very real concern. Travel carefully around trees, stay with a buddy, and if you haven’t yet seen this video please check it out. 

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.

Régions couvertes