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

Points saillants

Cool temperatures, soft snow, and enough wind to blow it around means triggering a small avalanche will be possible on Thursday. Expect to find soft slabs on very steep and wind-exposed alpine features, whether at the middle or upper elevations, and be ready for a small slide to grow as it entrains soft snow below. Since it will be hard to assess these zones for reactivity, the safest bet is to seek out the excellent riding conditions in less complex terrain.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    As we get further away from the most recent significant storm, potential slides are migrating into steeper and spicier terrain. Small soft slab avalanches have occurred in big terrain at the Pass over the last few days, where relatively light and subtle wind has loaded sensitive wind drifts into the start zone. That's all the evidence we need to know that continued cool temperatures and a bit more wind will make these slides possible again on Thursday.  While not breaking deep, these avalanches are growing as they run and grab the soft snow below.  If you see blowing snow, cracking, or fresh avalanches, you've got obvious clues telling you to make a more conservative plan, but you are unlikely to see these on Thursday. 

    You might actually need to be in a start zone in a steep and exposed alpine zone before you find evidence of instability, which is too late to learn about the problem. With that in mind, the safest bet is to avoid complex, consequential, and exposed slopes with sustained start zones over 35 degrees. Steep slopes below ridge lines, gullies, and aprons below cliffs are all zones to be on the lookout. If it looks like a double black at the resort, that certainly fits this definition. The image to the right of the page is a good example. That leaves a ton of fun riding to be had, and snow conditions are most excellent right now.

    (1/1/2025) Small soft slabs all over the place in the slot Photo: Ryan Stoddard

Avalanche Discussion

Thursday looks to be a bit of a repeat with a little bit of snow, a modest pulse of wind, and continued cool temperatures at the Pass. Though we are approaching 3 plus days since the last significant snowfall, the snowpack doesn't particularly care if the load comes from a cloud or the wind. Multiple parties in the backcountry near at the Pass are reporting localized wind-drifting, small human-triggered avalanches in specific features in big terrain, and a generally unreactive snowpack away from the wind-loaded slopes. A few observations have pointed to north-facing slopes holding wind loads further down than expected.

This type of subtle and light loading on top of a generally safe snowpack can present a tricky problem to manage as you can't necessarily see it or feel it below your feet/sled, and you've likely got to be in steep terrain to find signs of the issue. Really steep and unsupported terrain near the ridge line is the most likely, but not the only place to find instability. 

The bottom line is if you want to play in big terrain tomorrow, you shouldn't be surprised to find a soft slab. Though plenty of start zones won't have instabilities, some will, and knowing which ones do won't be easy. You'll need to have a strategy for managing this hazard. Also be sure to only expose one person at a time. If "managing the hazard" sounds scary, unreasonable, or like something that isn't in your risk tolerance, that's a perfectly reasonable response. If that's you, dial it back, avoid the big slopes, and have an awesome day in the mountains while these great conditions last!

Régions couvertes