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 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Loose wet avalanches are likely on steep sunny slopes with increased sunshine and warming Thursday.  You may find older wind slabs hiding under a few inches of softer snow near ridgelines.  It's still deep out there - ride with a partner and practice tree well and deep snow safety. 

Problèmes avalancheux

  • Loose Wet

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

    Cloudy conditions, cold temperatures and periods of light snow kept wet loose avalanches at bay on Wednesday.  With more sunshine likely Thursday along with slightly warmer temperatures, wet loose avalanches are still in play. 

    As the day heats up and if the sun comes out, look for pinwheels, rollerballs or natural wet looses releasing on very steep sunny slopes and beneath cliffs.  If you find the surface snow becoming wet and heavy, it's time to change aspects or move to lower angle terrain.  Be mindful of overhead hazard and the terrain you're connected to, wet loose avalanches may be found on a wider swath of the compass as we push later into March.    

    On shadier aspects, you can still trigger loose dry avalanches on very steep slopes.  Loose dry avalanches or sluffs, may not be big enough to bury you but could knock you off your feet and become an issue in terrain above cliffs, dense trees or a tree well. 

    (2/16/2024)

    Wet loose avalanches releasing from steep, sunny, and rocky terrain last month.  

    Photo: Julz Holder - Grounding Truth

  • Wind Slabs

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

    A few inches of new snow may mask older wind-stiffened snow on lee slopes at mid and upper elevations.  Older wind slabs are becoming less likely to trigger, but you should continue to use caution around steep unsupported terrain, on steep slopes below cornices and under cliffs where wind slabs can linger. 

    While backcountry travelers have been taking advantage of the break in the storm cycle and pushing further out, we still don't have a ton of information from higher elevation terrain where wind slabs are likely to be deeper and more consequential. 

     

     

    (3/6/2024)

    Identifying steep features with recent wind-loading near Whistler Lake in Canyon Creek. While most avalanche terrain was reasonable on Wednesday, most people stayed off the steepest unsupported features, especially if they had signs of recent wind-loading.

     

Avalanche Discussion

Observers found cold snow lingering on most aspects and elevations on Wednesday with continued cold temperatures and cloudy skies.  The snowpack continues to stabilize as we step further away from an impressive storm cycle and there were no new slab avalanches reported on Wednesday.  On Sunday and Monday, numerous natural and human-triggered storm and wind slab avalanches were observed within the top foot of the snow. Many of these crowns are now at least partially filled in by recent snow. By Tuesday, natural avalanche activity had come to an end and a few small human-triggered slab avalanches were noted.  

Since February 24 the Heather Meadows weather station has received 8 inches of water, and the snow depth more than doubled!  All of that storm snow continues to settle and backcountry travelers are reporting a slightly more supportable snow base than a few days ago when the trailbreaking was arduous at best. However, it's all relative - it's still very deep out there and tree wells and snow immersion suffocation are a major concern.  Enjoy the new snow safely; ride with a partner and practice deep snow safety.

Very large avalanches failed naturally throughout the zone and with explosive triggers near Mt Baker Ski Area during the height of the storm cycle and High avalanche danger last week.  Avalanches likely failed on weak layers either above the Early February Crust or above the 2/24 crust which are about 1ft apart in depth.  These layers are now 6-12ft beneath the surface depending on what part of the zone you're in.  We're not concerned about travelers triggering avalanches on layers this deep, but they're worth tracking as we head into another storm cycle and if you're traveling on or below slopes with cornices as temperatures rise later in the week. 

 Your avalanche, snowpack, or weather observations are extremely valuable to the avalanche community. Help create a more accurate avalanche forecast by submitting your observations HERE. 

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