Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

Forecast models vary, but no matter what, we'll be getting a little snow overnight and a bit more during the day, which is enough to increase our avalanche hazard. Identify wind-drifted features and avoid traveling on steep, wind-loaded slopes, where you're most likely to trigger an avalanche. At lower elevations, snow will get wet which could result in shallow wet slides, both natural and human-triggered, on steep slopes. 

Problèmes avalancheux

  • Wind Slabs

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

    You're most likely to trigger and get caught in a wind slab avalanche on Wednesday. Search for thicker, heavier deposits and textured or pillowlike surfaces. They tend to collect on one side of ridges and rolls, around rocky outcroppings, and in gullies. You can use small test slopes or simple hand tests to determine how snow is bonding to the underlying layer. In areas where you find drifts, avoid slopes greater than 35°.

    We expect most avalanches to fail at the new snow/old snow interface, so aside from the odd deeper wind slab, they will probably be less than a foot deep. At higher elevations, there's a small chance avalanches could be deeper, taking some of the snow we received over the weekend with them, which means there's a slight chance of avalanches 2 feet in depth or more. 

    (12/15/2024)

    Example photo: Small reactive wind slab formation, similar to what you might see on Wednesday. 

    Photo: Ryan Minton

  • Loose Wet

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

    Rain and warmer temperatures in the lower elevation band mean that you may see wet loose avalanches. These could occur naturally, or with a human trigger. If snow is sticky or wet, start thinking about wet avalanches. Scan nearby steep slopes for rollerball activity or small slides. If you see activity, avoid steep slopes and the areas beneath these slopes. If you enter steep terrain, you may trigger small wet slides as well. 

    (2/17/2025)

    Natural wet loose avalanches ran during the day in  the Stevens Pass zone on Sunday, Monday and Tuesday. They could happen as it's raining at lower elevations on Wednesday. 

    Photo: Roman Pavenko

Avalanche Discussion

Over the weekend, we received a little less than a foot of snow. Conditions in nearby zones went from touchy on Sunday, with widespread small human-triggered storm slab avalanches, but by Monday, there was much less activity. In the last couple days, the lower and most of the mid-elevation bands had gotten wet, and at least a subtle crust exists in most areas. Plenty of small semi-hard debris piles exist as well. New snow could slide easily on the firmer underlying layer, but uncertainty exists, so it may bond well and new snow might not be as reactive. 

The recent storm tested the persistent slab, which is now buried 3-4+ feet beneath the surface. Most neighboring zones didn't get any confirmed avalanches on the layer. An incoming warm wet storm this weekend will further test this layer. The neighboring Snoqualmie Pass, zone continues to be more active than other neighboring zones with recent slab avalanches, including several reported on Tuesday. 

If you get out in the backcountry, please share what you see by submitting an observation HERE or on the Avy App. 

Régions couvertes