Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

New snow and wind will create dangerous avalanche conditions at upper elevations by Thursday afternoon. You could trigger large avalanches on slopes greater than 35 degrees, especially in wind-loaded terrain. Increasing hazard throughout the day and poor visibility will require cautious route-finding and conservative decision-making.

Problèmes avalancheux

  • Wind Slabs

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

    Heavy snow and wind will form fresh slabs in leeward terrain that will become thicker and more reactive as you climb up in elevation. Be especially careful on easterly slopes and along large canyon walls. Look and feel for signs of wind-loading as you travel like blowing snow and changes in snow surface texture and hardness. If you experience shooting cracks or see recent avalanches, choose terrain less than 35 degrees and minimize overhead hazard. 

    Example photo: Look for cracking in wind drifted snow as you travel to highlight the potential for wind slabs on nearby slopes.

  • Storm Slabs

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

    Storm slabs will increase in size throughout the day as new snow accumulates. Use hand pits and inconsequential test slopes to assess the new snow looking for cracking, collapsing, or sudden and easy failures. New snow may fall with a favorable temperature profile - a warmer wetter start followed by gradual cooling. This may allow the new snow to bond well to old surfaces, but you will need to constantly evaluate and reassess throughout the day. The new snow will likely need time to settle and stabilize.  Choose supported terrain and avoid rollovers and steep open slopes. 

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

Avalanche Discussion

Mt Hood picked up 2-3in of new snow during the day Wednesday which accumulated on the 12/21 crust. Precipitation ramps up Wednesday evening before a lull overnight. Another cold front arrives Thursday morning as heavy snowfall resumes and snow levels lower throughout the day. 10-18in of new snow could accumulate above 5000ft by Thursday evening.

Avalanche danger will increase throughout the day Thursday. Pay attention to changing conditions, and choose conservative terrain especially during periods of heavy snowfall. Avalanche concerns will focus on new and wind drifted snow above the 12/21 crust. Below, the snowpack is generally strong and consolidated. While the new snow has been filling in the terrain, you may still find brushy vegetation and open creeks at lower elevations.

Régions couvertes