Bulletin d’avalanche

Blues

Wallowa Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

The 12 - 24" of new snow received early in the week is not bonding well to the old snow surface. Loose dry avalanches can be triggered on steep solar aspects where slick melt-freeze crusts exist. On northerly aspects a weak layer can be found below the new snow.  Carefully evaluate any slopes > 35 degrees for instability.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    1–1.5

    The 12-24" of storm snow earlier this week fell on a weak and uncohesive old snow surface. This is a significant amount of weight on a fragile weak layer.  While human-triggered avalanches are unlikely there are certain places in the terrain where a slab avalanche could be triggered. Carefully evaluate slopes > 30 degrees for instability. If you find over a foot of new snow sitting on weak layer of uncohesive snow, then move to lower angle terrain.  Avoid convex rolls, unsupported slopes, and pockets of wind-drifted snow on E-S aspects near and below ridgeline. Be sure to ski or ride on slopes one at a time.

  • Loose Dry

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

    This past weekend a potent storm system brought upwards of 2" of water equivelent to the Blue Mountains with over 3" of water shown at Milkshakes Snotel at 5600'. This translates into about 12-24" of new snow depending on your location. The new snow is not bonding well to slick crusts on solar aspects where slope angles approach 35 degrees or more.  The problem with loose dry avalanches, or sluffs, is on steep icy slopes the debris can accelerate quickly and carry you into trees, rocks, or over cliffs.  Avoid steep slopes where 6" or more of new snow is sitting on melt-freeze crusts from last week's warm up.

Avalanche Discussion

The Blue Mountains received significant amounts of snow early in the week. Most locations above 5,000' received 12" or more. This new snow is not bonding well to the old variable snow surfaces that range from stout melt-freeze crusts on solar aspects to weak uncohesive snow on more northerly slopes. It is time to be very dilegent in your snowpack assessment. There is alot of variability in snowpack structure and instablity across aspects. Do your homework before dropping in or on any slope greater than 30 degrees. If you are uncertain about the hazard - move to lower angle terrain. Remember...ski and ride one at a time. Avoid trigger points like convex rolls, rocky terrain, and wind-drifted areas below ridgeline. Choose slopes that are concave and don't funnel you into trees or into a terrain trap like a gully. Now is the time to dail it back and be cautious.

Régions couvertes