Bulletin d’avalanche

Olympics

Northwest Avalanche Center
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Danger d’avalanche

Sat
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

You can trigger a small avalanche where winds drift fresh snow onto pre-existing snow coverage.  New snow sits above bare ground except on shaded aspects.  The limited snow depth increases the consequences of a fall that may also result from a small avalanche.

Problèmes avalancheux

  • Wind Slabs

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

    The primary ingredients for an avalanche large enough to bury you on Friday will be (1) pre-existing snow coverage and (2) fresh wind loading from several systems arriving Thursday evening through Friday. You may start the day with minimal slab hazard and only a few inches of fresh snow, but your danger will gradually increase as the day progresses. Identify lens-shaped pillows atop relatively smooth pre-existing snow surfaces. Steer around these features on slopes steeper than 35 degrees, paying particular attention to the lee of ridgelines and underneath fresh, sharp cornices. In less wind-affected areas, you can still trigger a very small dry loose avalanche. Remember that shallow snow coverage magnifies the consequence of any avalanche capable of knocking you off your feet and into shallowly buried objects such as rocks or roots.

    (2/10/2023)

    You might trigger a wind slab in freshly drifted snow—Hurricane Ridge (lost bowl).

    Photo: Vince Reichheld

Avalanche Discussion

It's still early season at Hurricane Ridge and the season is long, so tread carefully as the snow stacks up once again. Dry late November weather left W-S-E aspects mostly bare of coverage near Hurricane Ridge. By contrast, storms through mid-November deposited up to 20" of snow on NW-N-NE aspects where you could already find smooth snow-covered surfaces before the 11/30 storm cycle. You might find the new snow residing on small surface hoar crystals above a crust-facet-crust combination. If you observe signs of a poor bond to the surface hoar, dial back your terrain selection. In most cases, as the new snow arrives with wind, the surface hoar gets knocked down, but it's worth examining the new snow / old snow bond, which could become more reactive with warming and further snow loading heading into the weekend.

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