Bollettino valanghe

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Pericolo valanghe

Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
1 · Debole
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In sintesi

Strong wind and an additional eight to ten inches of new snow in the past 24 hours continued to load avalanche start zones near ridgelines. This recent loading combined with the previous three days of snowfall has added stress to weak layers of snow which sit near the base of the snowpack. The remotely triggered and destructive hard slab avalanche which occurred yesterday afternoon on the west side of the Tetons indicates the potential for very large avalanches to occur. This avalanche was triggered from low angled terrain near a steep, wind-loaded ridgeline at around 9,600’. Widespread reports of collapses in the snowpack in middle elevations serves as a reminder that this persistent slab remains a potential problem there as well. Today is a good day to travel conservatively and allow the buried weak layers time to adjust to recent loading. Avalanche danger is Considerable today at upper elevations where very large, human-triggered slab avalanches are possible. Carefully evaluate the terrain where you plan to ride or better yet, stick to lower angled slopes where these slabs don’t exist. Elevations below 8500 feet have less snow coverage so Low avalanche danger exists there.

Problemi valanghivi

  • Wind Slabs

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

    Winds during the past four days of snowfall have drifted snow onto wind sheltered slopes. Signs of wind loading will include cornices, wind textures surfaces and stiffer surface snow underfoot. These slabs can crack and fail as thinner more sensitive slabs up to three feet thick or might break on more deeply buried weak layers and become much more destructive and unmanageable.

  • Persistent Slabs

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

    Weak snow that formed during a prolonged dry period and was buried on December 5th remains a layer of concern in terrain above 8500 feet. This avalanche type could be triggered beside or below a steep slope and could be triggered on a slope that has many tracks. A very large avalanche could occur on this problem layer especially where a thick slab lays on top. A slab avalanche with a crown up to ten feet thick was reported yesterday afternoon on a wind loaded slope west of the Tetons.

Avalanche Discussion

( Discussion is generated from the previous day's afternoon forecast. )This evening, an Arctic cold front will push through western Wyoming and bring with it a brief period of snow and high wind, which will shift to the northwest, as the front passes. Only an inch or two of snow will arrive with the front but temperatures behind it will drop significantly. Expect highs in the mountains tomorrow to struggle to reach single negative digits after overnight lows of -10 to -15. Frigid temperatures and very little, if any, wind loading are expected tomorrow. These factors will make natural avalanches trend towards unlikely in the Tetons and Togwotee Pass and so reduce the overall avalanche hazard in those areas to Moderate. The Grey’s River area appears to have a potentially more active weak layer, which has received the same or greater stress from recent storm snow and wind loading. Though we do not have strong confidence that natural avalanches will occur there, the increased thickness of slabs there, which could be up to five feet thick, and the potential to trigger these from a distance or from below shouldn’t be ignored. These factors result in a Considerable danger rating at upper elevations, on steep and wind loaded slopes above 8500 feet in that zone.

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