Bulletin d’avalanche

Central Cascades

Central Oregon Avalanche Center
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Danger d’avalanche

Wed
Alpin
1 · Faible
Limite forestière
1 · Faible
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

Very light snowfall on Tuesday will do little to change the avalanche hazard.  Avalanches large enough to bury or injure a rider would be surprising.  We have several persistent weak layers in our upper snowpack, but they have not been weak enough to produce avalanches.  As always heed any signs of instability such as audible whumphs or collapses in the snowpack and maintain safe travel techniques.

Problèmes avalancheux

  • Persistent Slabs

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

    We have two persistent weak layers in the upper snowpack.  Neither of these layers has proven weak enough for avalanches to occurr.  While persistent slabs remain unlikely it is worth evaluating these layers before committing to large, steep slopes that face North and are near or above treeline.

    We have been finding a layer of buried surface hoar that is down 20 cm. and present on sheltered slopes predominently near treeline and just above.

    The second persistent  weak layer consists of poorly developed facets beneath a crust that is down 30 cm.  It is most prevalent and weakest on the coldest slopes (shady North slopes near treeline and above).

    These layers may become a concern as we receive a substantial amount of new snow (hopefully next weekend and into next week).

Avalanche Discussion

Tuesday will be a day of transition with a little new snow and increasing winds.  While snowfall forecasts of 1" are too little to include Wind Slabs in our problem list, there is soft snow from Saturday lingering that is available for transport, and I expect VERY shallow Wind Slabs will begin to develop by afternoon/evening (again, too shallow to include as an avalanche problem).

In regards to the persistent weak layers in our upper snowpack:  this is a great time to remember/refresh your compression test skills.  Sudden collapses and sudden planar fracture characters (think "pops" and "drops") have been associated with avalanche activity.

Régions couvertes