Bulletin d’avalanche

Stevens Pass

Northwest Avalanche Center
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Danger d’avalanche

Tue
Alpin
3 · Marqué
Limite forestière
2 · Modéré
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

We'll get a few inches of snow during the day before a large storm begins Monday night. You may be able to ride some slopes without triggering an avalanche, but on other slopes you might trigger an avalanche which could fail up to about 2 feet deep. Consider avoiding steep slopes, especially at upper elevations, as a large avalanche could result. 

Problèmes avalancheux

  • Storm Slabs

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

    As the storm came to a close on Saturday, several natural and human-triggered avalanches were reported. Conditions are slowly improving, and there was less avalanche activity reported on Sunday.  It's a gamble on whether slopes will slide are not, and with a sizeable storm being only 2 days old, it's best to stay conservative with your terrain choices.

    If you trigger a slide, it may run just above a recent crust, and could be 1-2 feet deep. However,  slides have the potential to step down to any number of weaker snow layers, up to 3ft deep on older, sometimes slick crusts. With multiple potential weak layers, it'll be prudent to look for more supported and lower-angle slopes to ride on. Avoid slopes steeper than 35° at upper elevations, especially large, unsupported ones with high-consequence terrain below. 

    If we get more snow than forecasted on Monday, consider stepping further back if you notice red flags or heavier slabs forming in the new snow. Avalanches may just run shallower in the new snow layer. 

    Example photo: A large, human triggered slab avalanche similar to one that you could trigger on Monday. 

    Photo: Josh Hirshberg

Avalanche Discussion

The Stevens Pass zone received about 1-2ft of snow since New Years.  A skier was caught and carried a short ways in a 1.5ft deep slide on the north side of Valhalla Peak on Saturday. Luckily no burial or injuries were reported. They reported hearing a whumph when it broke, and it ran on a soft crust (potentially the 12/30 interface). 

Over the past week, observers have been finding sudden and propagating failures with crust, and facet/surface hoar layers that date all the way back to the Solstice. These layers can be found 1-3ft down beneath the storm snow. At mid and upper elevations you may find a slick, translucent crust with facets and/or surface hoar above or within. These layers are widespread around the region, and are likely to play a role with larger avalanches as the snowpack gets deeper. Once we get more snow, beginning Monday night, we expect a large, natural avalanche cycle which will likely produce avalanches on underlying weak layers. 

Travel conditions and coverage are still thin, but improving by the day. Beware of hitting exposed rocks, stumps, and creek openings, especially at lower elevations. You can contribute to the forecast! Let us know what you found by submitting an observation HERE. 

Régions couvertes