Bulletin d’avalanche

Snoqualmie Pass

Northwest Avalanche Center
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Danger d’avalanche

Sun
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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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 the snow starts to settle and gain strength, you’ll want to focus your attention on avoiding features where you may still trigger an avalanche in the recent snow. Be leery of steep unsupported slopes, convex rollovers, and wind-loaded areas below sharp cornices.

Problèmes avalancheux

  • Storm Slabs

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

    While you may find subtle inter-storm layers within all the recent snow, observations generally indicate a strengthening upper snowpack that is well bonded to the underlying crust. This is all great news. When conditions get like this, we often start to focus on likely trigger points- areas where we’re more likely to cause an avalanche. These places include steep unsupported slopes, rocky complex terrain, convex rollovers, and wind-loaded features. You can take time to identify these locations and steer around them to reduce the likelihood of triggering a slide. 

    If you head to the higher peaks around Snoqualmie Pass, you may find that the wind drifted the new snow into slightly firmer and thicker slabs. Look for sharp cornices and drifts to help you anticipate wind-loaded slopes. These are the locations you’re likely to encounter larger and more dangerous avalanches.

    (12/30/2022)

    Hand pits can allow you to look at the upper snowpack layers and how the new snow has bonded to the old surface. 

    Photo: Dallas Glass

Avalanche Discussion

A slight cooling trend and a few more inches of snow should help the snowpack continue to settle and gain strength Saturday. While the danger slowly drops, don’t forget it’s been quite a wild weather week at the Pass. Just within the last 7 days, we’ve swung from arctic temperatures, to freezing rain and sleet, to all rain, and back to winter. It can feel a bit like whip-lash. This was a big change to the snowpack, and even those wet avalanche concerns aren’t fully off of our minds. Water continues to drain from the snowpack. You may notice blown-out creeks, rushing waterfalls, and open holes. While we, think it would be very unlikely, we can’t rule out a glide avalanche still occurring. If you see crevasse-like cracks on a slope, don’t linger underneath it.

Since temperatures cooled this past week and winter returned, the Pass has received 12-18 in of snow (1.44in S.W.E) at mid-elevations. Below ~4500ft, this snow is well bonded to a very thick and strong crust. Above, the new snow sits on a still relatively wet snowpack. While it has started to freeze, the crust is much less supportable at these higher elevations. 

Near and below Pass level Saturday, wet heavy snow may produce rollerballs and small loose wet slides. While cooling temperatures should limit these concerns, don’t let one of these avalanches catch you off guard near a creek or gully.

Régions couvertes