Bulletin d’avalanche

Snoqualmie Pass

Northwest Avalanche Center
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Danger d’avalanche

Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

As you ascend in elevation, keep an eye out for wind-loaded features to avoid. They’ll be more likely on steep convex slopes, near ridgelines, or in rocky areas. Some uncertainty around continued snowfall amounts Wednesday evening puts the size of these potential avalanches in doubt.

Problèmes avalancheux

  • Wind Slabs

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

    The most likely location for you to trigger an avalanche should be in wind-loaded terrain on Thursday. Keep an eye out near ridgelines, confined chutes, or the base of cliffs where wind-drifted snow likes to accumulate. Visual clues such as newly formed cornices or pillow-like piles that look “fat” can help you identify wind-loaded features you’ll want to avoid. 

    While wind-loaded terrain is the most likely location for triggering a slide, that doesn’t mean you can’t trigger avalanches on steep slopes that are more wind-sheltered. Soft slabs or Dry Loose avalanches could potentially run far and fast on the most recent 1/14 crust. In some instances, they could break in some surprising ways. So use hand pits and test slopes to investigate for potential weak points in the newly fallen snow and keep a lookout for red flag signs of instability such as shooting cracks.

    (1/16/2023)

    A wind slab avalanche along the base of cliffs on Bryant Peak in the Alpental Valley. E, 4800ft, SS-U-D1.5-R2U

    Photo: Jeff Tarshis

Avalanche Discussion

As of Wednesday afternoon, the Pass has picked up close to 7 inches of new snow during this quick storm. Snow totals by Thursday morning are a bit of a question mark due to uncertainty surrounding a convergence zone impacting the area this evening. We’re banking on getting a few more inches out of the convergence. But if the snow really stacks up, we could potentially end up with some higher hazard at upper elevations. You may find that the new snow is most reactive first thing in the morning. Additionally, with the sun possibly making an appearance on Thursday, keep an eye out on the snow surface to see how it might be changing. You could see some loose avalanches or rollerballs as snow sheds from trees and rocks.

All of the recent snow is falling on the 1/14 atmospheric river crust. At mid to upper elevations, this interface should be about a foot below the surface but only a few inches deep at lower elevations. Any avalanche on Thursday should be confined to this snow which could contain a few interstorm layers to investigate. In some areas of the zone, a poor bond to this interface has resulted in recent Wind Slab and Loose avalanches. Let’s try to buck this trend as we move into some nicer weather in the coming days.

Régions couvertes