Bulletin d’avalanche

Central Cascades

Central Oregon Avalanche Center
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Danger d’avalanche

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

Points saillants

Avalanches will be likely on Friday due to the effect of very warm and sunny conditions on the snowpack. As the snow surface becomes wet and slushy, decrease your exposure to avalanche danger by moving to lower angle slopes, out from under big steep slopes, and/or move to slopes that are not as affected by the warming.  

Problèmes avalancheux

  • Loose Wet

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

    This one is the most predictable of the problems on this list for Friday. It will be a warm and sunny day and the surface snow will become wet and slushy. Monitor how deep the snow is becoming wet. If you find you are sinking into slushy snow to boot top or deeper, wet loose avalanches have the chance to become large. These avalanches will be more common on steep slopes where the slushy snow has the propensity to spill downhill. During the warmest time of the day the lowest elevations in the forecast zone will have a daytime high temperature that will rise into the mid 70's making wet loose avalanches possible even on the shaded northerly aspects. 

    Timing and aspect is important in managing this problem. Wet loose avalanches will be more likely on slopes in the direct sun. If you have certain objectives in steep terrain, it will be wise to be off the terrain by the time it is in the direct sun, especially during the warmest time of the day. 

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2.5

    Warm temperatures can weaken existing cornices. Avoid walking out onto a cornice and minimize the time you spend underneath them. Many overhanging cornices have already broken off, but there are still some out there hanging on.

    Cornices can be found along  ride tops hanging over north and east facing slopes. There are a few sneaky cornices lingering above cliffs and wind exposed ridges below treeline. 

  • Wet Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3

    With above freezing temperatures overnight and very warm temperatures forecasted during Friday, layer boundaries in the mid and upper pack have the chance to weaken and fail leading to wet slab avalanches. Melting of the snow surface can lead to free water percolating into deeper layers, further weakening bonds in the snowpack. Recognition of this problem includes looking for wet slushy surface snow, pinwheels, and wet loose avalanches. If you observe small wet slabs, this is a good indicator that larger wet slabs are also possible. The size of these avalanches is hard to predict, but they have the chance to be very large. 

Régions couvertes