Bulletin d’avalanche

Central Cascades

Central Oregon Avalanche Center
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Danger d’avalanche

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

Points saillants

On Saturday, avalanches in wind drifted snow will be possible at mid and upper elevations. In north-facing areas that have been been protected from the wind and sun in recent days, small avalanches could spread farther than you might expect. Avoid this hazard by sticking to low-angle or low elevation, wind-sheltered slopes. 

Problèmes avalancheux

  • Wind Slabs

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

    With new snow and winds out of the south, wind slab avalanches will be possible on north-facing aspects near and above treeline on Saturday.  As the winds shift from the southwest to the southeast, watch for crossloading on west and east aspects. Generally, with light winds and several inches of snow in the forecast for the next 24 hours, I would not expect particularly large or reactive wind slabs. The tricky thing is that our field team has been finding surface hoar over the past few days, which could pose a problematic weak layer once it gets buried by this new snow.

    On Saturday, watch for the typical signs of wind loading: wind-blown snow near ridgetops, new drifts and cornices forming, and rippled textures or smooth pillowy snow surfaces. In addition, look for signs of "strong over weak" as the new snow stacks up. This could include shooting cracks, whumphing, or small avalanches propagating farther than you expect. Using tools like hand shears, stepping on small rolls (test slopes), or digging a small pit in the new snow will help you gain information about the changing snowpack. Skiing low angle terrain or open glades below treeline would also be good options for avoiding this problem. 

Avalanche Discussion

On Friday and Saturday, observers reported widespread surface hoar at mid-elevations (6-8k'), especially in areas that are protected from the wind and sun, though the surface hoar was also found over a melt-freeze crust on east aspects. While it hasn't been a problem yet, and it's made for some nice riding, surface hoar can become a weak layer if it gets buried while it's still intact. Rain, sun, warm temperatures, and wind are things that can disrupt the formation of this weak layer.  As new snow piles up in the coming days, this is a layer that the COAC team will continue to monitor. Time will tell whether it becomes a weak layer that sticks with us. 

Régions couvertes