Bollettino valanghe

Tetons

Bridger-Teton Avalanche Center
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Pericolo valanghe

Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

Today, avalanche conditions are dangerous. Recent snowfall of over 40 inches this week and strong winds have formed new surface slabs on leeward slopes and added stress to deeply buried weak layers. Natural avalanches are still a possibility and human-triggered avalanches are likely. After this most recent loading event, avalanche activity on the December 5 interface is a reminder of the persistent nature of this layer. Along with the high consequences of the persistent slab problem, wind-loaded slopes have the potential to result in large avalanches. In managing these avalanche problems, it is important to avoid wind-loaded terrain, stay out from under avalanche terrain, and avoid avalanche runouts. At the lower elevations, human-triggered avalanches are possible on steep terrain features.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Sustained southerly to westerly winds in the 30s and 40s with strong gusts to the valley floor have redistributed the snow and formed wind slabs at all elevations. The gusty nature of these winds have formed unusual loading patterns, making it important to evaluate terrain features with recent wind effect. These slab avalanches could be 1 to 4 feet in depth with the deeper slabs favoring the upper elevations. If triggered, a wind slab avalanche could then initiate failure on deeper buried weak layers.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    Weak layers of snow now buried between 4-8 feet deep have been stressed and tested over the last five days. Evidence of recent avalanche activity indicates this layer is still reactive to being triggered. These slides could be triggered by a single person from a thin part of the slab or by large loads such as snowmobiles and wind slab avalanches. Due to the severe consequences of involvement in an avalanche of these depths, the best approach to this uncertainty is avoidance.

Avalanche Discussion

A weather system will exit to the east as a ridge of high pressure builds from the west. Cloud cover will continue to decrease overnight and then, skies are expected to be mostly sunny tomorrow. Temperatures will be cold starting in the single digits and then warming into the teens in the mountains and twenties in the valleys. Ridgetop winds will be westerly at 10 to 20 miles per hour. Dangerous avalanche conditions continue to exist above 8,000 feet, where the avalanche hazard will remain Considerable. The weight of a single person could trigger a large to very large avalanche that would result in severe to deadly consequences. When dealing with persistent weak layers that are buried several feet deep, warning signs of cracks and collapses will probably NOT be encountered and previous tracks do NOT indicate stability. As winds abate, wind slabs will become less likely to trigger. Although, the release of a small slide could initiate failure on deeper layers and result in a much larger avalanche. Careful travel through avalanche terrain and snowpack evaluation will be important to safely move through the mountains.

Regioni coperte