Bulletin d’avalanche

West Slopes South

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

Points saillants

A frozen surface will create lower avalanche danger in the morning. Once it thaws, you may trigger slides in places with more than 4 inches of wet snow. Travel early and be back at the car before things get too wet and unstable. 

Problèmes avalancheux

  • Loose Wet

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

    You’re really dealing with two different versions of wet loose avalanches. You may trigger the smaller and more predictable version once the surface crust softens and the wet snow is deeper than your ankle. When you find wet manky snow, head to more shaded aspects or lower-angled slopes. As warm temperatures and sunshine reach around the dial, you could trigger these slides on any aspect by the afternoon. 

    A second, less predictable, and scarier type of wet loose slide could occur in isolated areas. These avalanches happen when a blob of snow gouges deeper and allows the slide to grow larger. You will primarly see them release naturally near and below cliffs on E-S-W aspects. Limit any time you spend under this type of terrain during the heat of the day. 

    Similarly, other shed-style avalanches (cornice falls, glides, and wet slabs) could occur. The longer we go in this warm period, the more higher the uncertainty grows. These unpredictable slides can release regardless of the time of day. Manage your overhead hazard by minimizing or eliminating any time you spend on or under snow-covered rocky faces and looming cornices.

    Wet loose slides from Saturday. (3/30/2024) Photo: Lauren Walker

Avalanche Discussion

Preliminary Report: NWAC is saddened to report an avalanche fatality as a result of a cornice fall on Mount St. Helens. On Friday, March 29, 2024, a snowboarder summited the peak. While standing near the top, he triggered a cornice and fell into the crater triggering a large slab avalanche on the slope below. NWAC is working with Skamania Co Sheriff’s office and SAR to compile a report. Our deepest condolences to the family, friends, and community.

Discussion:

We’re in the middle of a prolonged period of warm spring weather. Sunday night and Monday, the high pressure ridge will really turn up the heat. Predicting wet avalanche cycles like these is nearly impossible. Activity can wax and wane, and avalanche activity could increase with little or no warning. Warmer temperatures Sunday night could result in a weaker freeze. Hot weather, sunshine, and lighter winds on Monday should easily allow the snow to soften.

On higher elevation north-facing slopes, you may still find cold dry snow and even a few wind-loaded pockets. A snowboarder in the Crytal backcountry triggered one such avalanche on Sunday. These slabs should be limited to the upper extent of our forecast region but may speak to conditions above it, particularly on the volcanoes.  

The weather may feel like spring, but on many slopes, the snowpack has yet to transition from its winter-like state. There could still be lots of surprises in store. Travelers over the weekend triggered numerous avalanches; some were caught, a few were carried and buried, and one was killed. Just because the sun is out doesn’t mean it’s safe. 

During this warm-up, we’re primarily worried about the snow over the 3/21 crust. On southerly aspects, the entire upper snowpack may just be melt forms at this point. In other locations, you should find this prominent layer 1-2 ft below the surface. 

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