Bulletin d’avalanche

Central Cascades

Central Oregon Avalanche Center
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Danger d’avalanche

Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
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

Avalanche danger on Tuesday will mirror the danger that we saw today.  Wind Slab avalanches will be possible on north and east slopes that the wind has blown snow onto.  We are continuing to warn about the danger of Deep Peristent Slabs and advising folks to avoid large, steep and unsupported slopes that may be shallow or rocky.

Problèmes avalancheux

  • Wind Slabs

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

    Wind Slab avalanches will remain possible on Tuesday.  Expect them on north and east facing slopes at higher elevations or anywhere that the wind is able to blow the snow.  Wind Slabs most often form down wind of terrain features like ridgelines.  With only inches of new snow on Monday morning and then 1-3 inches forecast for Monday night, Wind Slabs should be relatively shallow.  I expect they would only be large enough to bury or injure a rider on those slopes that have a particularly large fetch (area from which the wind can blow snow).  If you are choosing to ride on potentially wind loaded slopes, assess the cohesiveness of the surface snow on slopes that are less than 30 degrees or small enough that they aren't dangerous.  Cracking in the wind blown snow is the most common clue that points to a Wind Slab problem.  Hand shears are also a good "test" to determine how cohesive the surface snow is, and whether or not a weak layer is present.

  • Deep Persistent Slabs

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

    Are you getting sick of reading about our Deep Peristent Slab?  I'm a little sick of writing about it.  Sadly it is still something that we need to consider.  These deep slabs are unlikely but catastrophic events.  Deep Persistent Slabs are most often triggered from shallow trigger points, by other avalanches, or by cornice collapses.  The persistent weak layers responsible are now burried approximately 2 meters below the snow surface.  We don't get a lot of feedback on these weak layers because they are so deep.  I have been probing around a lot and it is still pretty easy to feel weak snow between the crusts from early season.  In time these grains will round and after some time with no avalanche activity or concerning test results we can stop thinking about this avalanche character.  In the meantime avoid big, steep, and potentially shallow slopes.

Régions couvertes