Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Additional heavy loading from new snow and wind will cause a natural avalanche cycle at upper elevations Friday. Avalanches could break several feet thick and run far distances. Travel in avalanche terrain is not recommended.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    2–3

    Another 12-18in of new snow over the next 24 hours will bring storm totals since 12/21 up to 2-3ft. Strong to extreme westerly winds will accompany the new snow, forming fresh drifts and thickening existing slabs. Avalanches will become larger and more widespread as you climb up in elevation. Only head out during the storm Friday if you are confident in your ability to identify and avoid avalanche terrain. Give yourself a wide margin for error and stick to simple, low-angle slopes away from overhead hazard.

  • Storm Slabs

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

    Storm slabs will increase in size and become more reactive throughout the day as new snow accumulates. Slabs could be just a few inches thick within the most recent storm layers or break up to 2ft deep on the crust buried 12/21. Avalanches will be most likely during periods of intense precipitation. Natural and human-triggered slides are expected in terrain 35 degrees and steeper, especially on unsupported slopes and convex rollovers. Give the new snow time to settle and stabilize before pushing into bigger terrain.

    (12/20/2021) Example of a small skier triggered storm slab from the last storm 12/18-20. Photo: Andrew Kiefer

Avalanche Discussion

Very dangerous avalanche conditions will develop Friday as another strong storm impacts the Northern Oregon Cascades. Snow levels will drop to 1500-2000ft as heavy snowfall continues through the day. Conditions will be dynamic, and the safest strategy will be to choose terrain less than 35 degrees away from avalanche path runout zones.

Mt Hood received 12-18in of new snow since 12/21, most of which fell in the past 24 hours. Blizzard conditions with poor visibility limited observations above treeline Thursday, but avalanche conditions were worsening and signs of unstable snow were easy to find. Human triggered avalanches were reported that broke 6-12in deep in new and wind drifted snow. Additionally, a very large natural avalanche (D3-4) occurred high on the east side of Mt Hood with debris running well below treeline into Heather/Clark Canyon. The timing of this avalanche is unknown, but it is suspected it ran during the last storm ending 12/20.

Deep snow will also be a hazard through the weekend. Watch out for tree wells and keep eyes on your partners. Learn more about deep snow safety HERE.

Régions couvertes