Bulletin d’avalanche

Snoqualmie Pass

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

Significant snow and several recent natural avalanches highlight the potential lingering danger. As the next storm approaches Saturday afternoon, conditions will only become more hazardous. You could trigger slides within the new snow on open slopes greater than 35 degrees.

Problèmes avalancheux

  • Storm Slabs

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

    There’s a lot of new snow at the Pass. While the storm snow weaklayers should be healing, don’t fully write them off. A surprising number of natural avalanches Friday morning shouldn’t be overlooked.

    Any steep open slope should be suspect. Hand pits and small slope tests may give you a glimpse into potential avalanches. However, you need to ensure you’re affecting all the way down to the rain crust to get a complete picture. 

    Increasing easterly winds could drift some of this snow into wind slabs in exposed areas at any elevation. Where you see blowing snow and firmer pillow-like slabs, you might trigger slightly larger avalanches. 

    (12/8/2023)

    Natural storm slab avalanches failed during a period of intense precipitation. 6-8 inches deep  SS-N-D1-R1-S

    Photo: Alpental Pro Patrol

Avalanche Discussion

The Pass got walloped by a Puget Sound Convergence Zone Thursday night. Impressive snowfall rates of 2 in per hour and greater quickly piled up snow. This resulted in numerous natural avalanches, particularly at mid and lower elevations. Most of these slides were only 6-8 inches deep and seemed to fail during the height of the storm very early Friday morning. Storm totals measured ~12 inches at Pass level and 28 inches higher in the terrain.

Complicating the situation is an incoming storm with increasing winds and additional precipitation. Conditions could be quite dynamic throughout Saturday, with the peak danger occurring late afternoon. 

Temperatures are expected to climb throughout the storm, with rain falling near the tops of the highest peaks by Sunday afternoon. Exactly when the warm-up will occur is very difficult to nail down. We expect very dangerous avalanche conditions to develop sometime Saturday night/Sunday morning, including large natural avalanches. 

While this snow helped travel conditions, the snowpack is still thin. Roaring creeks, open holes, shallowly buried rocks, and plenty of shrubs/trees continue to make travel tricky, particularly at lower elevations. Take it slow and give yourself time to deal with these travel hazards.

Régions couvertes