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
Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Triggering a Wind Slab avalanche will be likely on East and North slopes near treeline and in the alpine.  On Monday shallow Wind Slabs were observed near treeline on East slopes beneath touchy cornices.  Just how dangerous these avalanches will be depends on how much snow we receive overnight, which will directly contribute to the size of these avalanches.  If we receive another 6 inches of new snow, Wind Slab avalanches could be large enough to bury or injure a rider on isolated slopes.

Problèmes avalancheux

  • Wind Slabs

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

    On Monday I observed reactive Wind Slab just below the ridgeline of Tumalo Bowl (East, near treeline).  At this time of day there was only 7cm. of new snow and these Wind Slabs were shallow (20 cm.) and small.  For the past few days snowfall forecasts have been a bit optimistic and snow showers have under-delivered.

    Current forecasts for Monday night and Tuesday are totalling 15 cm or so.  Winds will be Moderate or Strong from the West and Southwest.  If we do receive 15 cm. of new snow, Wind Slab avalanches could be large enough to bury or injure a rider (D2) in isolated terrain.  Additionally Wind Slabs will be large on slopes with a particularly large fetch, or physical area from which the snow can be blown.

    Monitor how much snow is on the ground in sheltered locations, and then evaluate the Wind Slab problem on less steep, or smaller lee slopes.  Today the Wind Slab problem was pretty apparent:  I could see widespread blowing snow, extensive recent cornice growth, and lots of cracking in the 20 cm. or so of windblown snow on East slopes.

    (4/17/2023)

    D1 Wind Slab in Tumalo Bowl (East, near treeline)

    Photo: Gabriel Coler

  • Cornices

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

    Strong winds were causing a lot of Cornice growth on Monday, and these fresh cornices were touchy.  Be wary around Cornices, as many a seasoned rider has been surprised by just how far back cornices can break.  Cornices are pretty massive right now throughout the terrain.

Régions couvertes