Bulletin d’avalanche

Northern Wallowas

Wallowa Avalanche Center
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Danger d’avalanche

Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 6 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

In the last week the Northern Wallowa Mountains have picked up close to 2 feet of new snow and the Southern Wallowas close to 4 feet above 7,000'. This is a significant load and has stressed the existing snowpack creating unstable storm slab conditions. Natural avalanches have been reported in the Southern Wallowas on steep (> 35 degree) sun-affected aspects - south and west. Human-triggered avalanches are possible. Avoid and stay out from under slopes greater than 30 degrees. Avoid wind-loaded terrain features near ridgeline, especially north-east facing slopes. 

Problèmes avalancheux

  • Storm Slabs

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

    Expect to find unstable storm slabs on slopes greater than 30 degrees. These storm slabs may be anywhere from 12" to 48" deep. The new snow is not bonding well to the old snow surface, especially on south and west facing slopes where a stout melt-freeze crust exists at the old/new interface about 4 feet down. Avoid and stay out from underneath slopes greater than 30 degrees. Be conservative in your terrain selection for the next few days as the snowpack adjusts to all the new snow. 

  • Wind Slabs

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

    Moderate westerly winds overnight picked up and moved the light fluffy new snow onto leeward terrain features near ridgeline likely creating pockets of reactive and unstable wind slabs. These wind slabs may be 12" to over 24" thick in some locations. Avoid N-E facing slopes greater than 30 degrees in the alpine and especially near ridgeline. Avoid smooth rounded pillows and cross-loaded terrain features mid-slope. If you go from sinking in a foot or more on your skis, board, or snowmobile to riding right on top, then you are likely on a potential wind slab. 

Avalanche Discussion

Our area mountains in the last week have been dumped on. Some locations like Norway Basin have received over 4' of new snow above 7,000'. This is a significant load and strain on the existing snowpack. The best recipe for avoiding avalanches is to make conservative terrain choices for the next few days. The snowpack needs time to adjust to this new load. Keep your slope angles low...below 30 degrees. There is plenty of good riding out there right now on those lower slope angles. The snow quality is high. Be patient...there will be an opportunity to ski and ride steeper terrain a bit later down the road. 

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