Bulletin d’avalanche

West Slopes North

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

Expect unseasonably warm conditions and wet avalanche activity. Keep an eye on steep slopes overhead, especially those seeing strong, direct sunshine. Avoid traveling on or below terrain where you observe rollerballs, snow shedding from rocks, small avalanches, or glide cracks.

Problèmes avalancheux

  • Loose Wet

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

    Sunday is forecast to be the warmest day since the sun came out. Widespread wet avalanche activity is not expected. But if you were to see or trigger a wet avalanche, then it would be the day. While there is a much higher probability of seeing wet avalanches on solar aspects, any slope can become unstable if it gets warm enough.

    Glide avalanches - when the entire snowpack peels off smooth ground below it - are also possible during warm conditions. One natural glide avalanche was reported today and some more are expected tomorrow. Given the shallowness of our current snowpack most should be smaller in size. But it would still hurt a lot if you were in the way. There are also plenty of terrain traps and other hazards out there that would magnify the consequences of being caught in any avalanche. Look for and stay out from under glide cracks or snow clinging onto exposed rock slabs (see photo).

     

    (12/16/2023)

    A natural glide avalanche on Herman occurred midday Saturday. The cracks on either side of the avalanche bed surface indicate more portions of the slab could also slide off the rock below.

    ENE aspect at 4700' (WS-N-D1.5-G).

    Photo: Pete Durr - USFS

Avalanche Discussion

Look out for pockets of wind slab if you head up into the alpine. Continued alpine winds likely drifted any loose snow available for transport. A small wind slab avalanche can still carry you over a cliff or into a crevasse. 

Observers reported slightly cooler conditions on Saturday. Temperatures were a few degrees lower, ridgeline wind speeds were a bit higher, and there were more high clouds. Clear skies Friday night made for a shallow refreeze despite overnight low temperatures well above 32F.

Total snow height varies from pretty much nothing at low elevations to 3-4' at upper elevations. The current snowpack consists of alternating crust and rounded grain layers. This structure shows the hard swings between dry snow, rain events, and high pressure we've seen since November.

There are still plenty of open creeks, exposed or partially buried rocks, stumps, and old, chunky avalanche debris. Stay vigilant to early season hazards.

Régions couvertes