Bulletin d’avalanche

Snoqualmie Pass

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré last year. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

On Friday, the wind may drift new snow into unstable slabs at upper elevations. Elsewhere, our snowpack is saturated, and unpredictable wet avalanches could still occur. Choose travel routes that limit your exposure to overhead hazards.

Problèmes avalancheux

  • Wind Slabs

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

    Above the rain/snow line, there may be just enough snow and wind that you'll need to put dry snow problems back on your radar. Look for potential slabs in wind-loaded areas, such as leeward ridgelines, the sides of gullies/chutes, or the base of cliffs. You can look for texturing of the surface or new pillow-like drifts to help identify wind-loaded features that you should avoid. Using uptrack tests or small test slopes can help you determine how the new snow is bonding to the old surface. In most locations, we anticipate a fair to good bond. The general cooling trend means storm snow should come in right-side up, but quick hand pits can help identify midstorm instabilities that you may need to manage. 

    (3/12/2025)

    A shallow wind slab from earlier this month.

    The textured surface and a stiffer feel to the snow can help you identify wind-loaded features to avoid.

  • Glide Cracks

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3

    While new wind slabs may be the more "in-your-face" problem on Friday, this is the one that you need to worry about. Our snowpack is saturated from this week's atmospheric river and unseasonably warm temperatures. We haven't had a good overnight freeze in almost a week. Wet avalanches are impossible to predict and can often occur long after the rain has stopped. Although cooling generally helps resolve these issues, the initial cool-down can sometimes trigger a final round of slab or glide activity. We've seen this movie before at Snoqualmie Pass. We think the storm is over, and then, boom! A rogue glide comes down and leaves everyone scratching their heads. Well, not this time. Now, you'll be ready to avoid large avalanche slopes where one of these low-likelihood, high-consequence slides could occur. Even if some new snow covers up the glide cracks or that sagging cornice has a crack that's filling in, you'll know that you need to limit the amount of time you spend below steep, rocky terrain. If a wet avalanche releases, it will occur without warning and will likely be unsurvivable. So, avoid putting yourself in a position where you could be caught off guard.

    (3/27/2025)

    A glide slope that released down to the rocks. Next to it, you see a glide crack where the slope has not yet released but could with additional influence. 

    Photo: Andy Harrington

Avalanche Discussion

After a warm and wet week, temperatures are starting to fall, and soon, snow may follow. Some mountain stations dropped over 20 degrees F in a 24-hour block. That trend should help us solidify the surface and eventually put an end to wet avalanche problems. In the coming days, we'll likely refer to this surface crust as our new ground and discuss dry snow problems above it. Until that happens, we will have to deal with the great uncertainty that wet avalanche problems present. Glides, gouging wet loose, and cornice collapses remain very real threats as the surface starts to stiffen, and we return to a stormy pattern. Although we anticipate snow at higher elevations, you can expect rain down low, meaning blobs of snow could still fall off rocky ledges or slopes that only partially released this week. Abundant glide cracks and running water were observed at the Pass on Thursday, so there's plenty of opportunity for further failures despite the snowpack being reasonably well-drained. 

Expect to encounter sloppy and soggy travel conditions at lower elevations before ascending to snowier ones. Recent avalanche debris, open creeks, and exposed ground now litter the landscape, so allow yourself extra time to navigate these hazards. 

Régions couvertes