Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 6 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

 You can easily trigger a large and dangerous wind slab in near and above treeline terrain. Given the strong to extreme winds through Friday morning, you may find these slabs extending well below their typical start zones.  Give these slabs some respect by avoiding wind-loaded terrain steeper than 35 degrees. 

Problèmes avalancheux

  • Wind Slabs

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

    You can trigger large and dangerous wind slabs near and above treeline. We expect 10-12" of snow to be transported by strong to extreme winds, wind-stripping or loading most slopes near and above treeline. Snow may deposit on mid-slope terrain features and where you don't expect them. Slabs are likely to be large, firm, and difficult to escape in exposed terrain. Seek wind-sheltered terrain where possible. Avoid areas of active snow transport and wind-loading. Pay attention to cracking snow surfaces and firm, punchy layering. Avoid all wind-loaded slopes steeper than 35 degrees.

    Below treeline, slabs may be smaller, softer and easier to steer around if you can identify the subtle, stiffer slab or find 8" of fresh snow. In either case, keep your slope angle below 35 degrees and avoid convex rollovers.

     

    Blowing snow, firm and textured snow, and cornice formation are all evidence that wind slabs are likely to be forming on lee slopes.

Avalanche Discussion

Mt Hood Meadows Pro Patrol reported a stabilizing upper snowpack on Thursday. The only avalanche activity involved Wet Loose on south-facing slopes due to warming and partial sunshine on the east side of Mt. Hood. You may find a thin temperature or light "mist" crust on southerly aspects extending up to 7000 ft. This thin crust may be a plane of failure for avalanche activity in some areas on Friday. 

The stout mid-January crust is considered the new "ground" with a strong snowpack structure in place below this layer. Weak and faceted snow just above the stout rain crust was responsible for a number of avalanches Thursday-Saturday, but no new evidence of avalanches on this interface suggests these facets are gaining strength. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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