Bollettino valanghe

Turnagain Pass and Girdwood

Chugach National Forest Avalanche Center
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Pericolo valanghe

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Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Chances of triggering an avalanche are decreasing, but there are still several avalanche problems to keep in mind today. There will still be isolated pockets of wind-drifted snow that can produce avalanches around 1 to 2' deep in previously wind-loaded terrain. There is also a smaller chance of triggering a much larger avalanche failing on a weak layer of snow buried 2 to 6' deep on average. As temperatures warm in the alpine, we may see some small loose snow avalanches failing naturally in steep south-facing terrain.

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It has been a tragic week of fatal avalanche accidents in the lower 48. In addition to the accident involving a large group outside of Lake Tahoe, there were two fatal accidents in Utah. Our thoughts are with the victims, their friends and families, and all of the responders involved. Preliminary information may be found at sierraavalanchecenter.org and utahavalanchecenter.org.

Problemi valanghivi

  • Deep Persistent Slabs

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

    Recent Avalanches: Human-triggered avalanches were reported on Raggedtop and Tincan on Thursday. We've seen several natural wind slab avalanches that occurred during last week's outflow event, most of which were in the 1 to 2' range and around 50 to 100' wide. There was a larger avalanche on Fish's Breath in Girdwood on 2/14, which failed on a deeper weak layer and gouged down to the ground as it ran.

    We are expecting a quiet day of weather, but several avalanche problems remain on our radar. The main concern is the lingering chance of triggering a large avalanche failing on weak snow buried 2 to 6' deep. While this has become very unlikely in most locations, it is still a concern in isolated terrain. The natural avalanche outside of Girdwood last week was a key indicator that the layer has not gone away, and it's worth keeping in mind as you travel.

    This problem is most concerning in areas with a thin snowpack. The structure is more concerning on the west side of the Girdwood Valley, including the Crow Creek area. There may also be some isolated slopes in the core of Turnagain Pass where this layer can produce an avalanche. This would be most likely in terrain that has been previously wind- scoured, but from what we have been tracking over the past few weeks this is becoming very unlikely.

    Loose Snow Avalanches: Chances for loose snow avalanches will increase as south-facing slopes heat up through the day. The relentless winds from the past weeks have locked up snow surfaces, which will limit the extent of any activity. These will be most likely on solar aspects with rocks or trees, especially in terrain that has any soft snow on the surface. The front side of Seattle Ridge is one example of where we may see some of this activity.

    Cornices have grown large over the past week, and will be heating in the sun for the next few days. As always, avoid spending time under this overhanging hazard as they can release unexpectedly.

  • Wind Slabs

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

    The winds have done major damage to the skiing and riding conditions over the past week. At this point there is very little snow available for transport, and any new wind slabs forming today are unlikely to be more than a few inches deep.

    However, some of the slopes that were loaded over the past week have a thin crust buried just below the surface, which may cause these lingering wind slabs to remain reactive today. Be on the lookout for isolated pockets of unstable snow in previously wind-loaded pockets. These will have a smooth, pillowed texture and will feel stiff or hollow. With the extreme winds we saw at the end of the week, these may allow you to travel well out into the middle of the slope before triggering an avalanche.

Regioni coperte