Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

Your likelihood of triggering a large slab avalanche is decreasing, but the consequences remain severe. Your danger will be greatest above treeline, so ascend with caution, navigating around steep wind-loaded slopes and terrain rollovers.  Use evidence from wind-scoured ridgelines and recently formed cornices to identify likely wind-loaded slopes nearby.

Problèmes avalancheux

  • Wind Slabs

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

    Strong winds on Saturday redistributed 11-12" of snow that fell Friday into Saturday morning. This produced Wind Slabs up to size 2.5 (large-very large), with crowns 1-3 ft deep that Mt. Hood Meadows Pro Patrol triggered via large explosives. Some broke within the storm snow while others stepped down new/old snow interface. The likelihood of triggering such a slab continues to trend downward, but don't let your guard down some of these avalanches will bring low chances of survival. Firm and textured snow, cornices, and collapsing or "whumphing" sounds in the snow are evidence that you could trigger a wind slab on similar aspects. Navigate around places where you are most likely to trigger an avalanche, such as where a steep slope further stepens (rolls over). Human-triggered wind slabs running down to the crust in adjacent zones (see photo), remind us that humans are triggering avalanches and we think that is still possible tomorrow. 

     

    (12/27/2020) This large avalanche in the Crystal Backcountry was 2-3 feet deep and 200+ feet wide. It ran across 3 cross-loaded gullies and had an unknown trigger. [NE side of Crown Point ~6460']

Avalanche Discussion

Mt Hood received a good shot of snow Christmas day and the wind has redistributed it into fresh wind slabs. 

While Wind Slabs are the primary problem, in sheltered terrain below treeline, small pockets of storm slab could be triggered on steep terrain features on Sunday. In spite of plenty of sunshine, cool temperatures and a low sun angle prevented Loose Wet activity from developing. 

Storm slabs should continue to heal, but may still produce small avalanches on isolated terrain features such as convex rollovers or extreme terrain.

Although we expect that one day of sunshine was sufficient test of the Wet Loose potential, warmer temperatures and more sunshine means that small Wet Loose avalanches can't be ruled out. Adjust your aspect and reduce your exposure to steep slopes above if you see rollerballs.

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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