Bollettino valanghe

Turnagain Pass and Girdwood

Chugach National Forest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

It will be easy to trigger an avalanche up to 2’ deep on a layer of buried surface hoar. This can be found at mid and upper elevations and will be more concerning where fresh wind slabs have formed over this layer. Active wind loading is expected to create new wind slabs as well as add stress to cornices at upper elevations. This weak layer is tricky to assess so the safest option is to avoid steep slopes especially wind loaded terrain. 

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1.5–2.5

    That pesky surface hoar layer buried up to 2’ deep is still guilty of causing human triggered avalanches. This will be the main concern today at mid and upper elevations. On Sunday we heard reports of small human triggered avalanches in the Tincan trees. It seems like this layer is more widespread on sheltered slopes between 1,500' and 2,500’ and harder to find on slopes exposed to the wind. It will be even easier to trigger this weak layer where wind slabs exist. 

    The tricky thing is knowing where these weak layers are and how weak they are. Traveling tests such as hand pits may or may not produce concerning results. Listen for whumpfs and look for shooting cracks underneath you. Test small safe slopes to see if you can trigger a small avalanche. The main point is that just because you don’t find them does not mean they are not there. Rather than trying to outsmart the problem it is safer to enjoy soft snow in less consequential terrain.

  • Wind Slabs

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

    Strong overnight winds have created wind slabs up to 2’ deep that will be easy to trigger at upper elevations. Ridgetop winds from the east are expected to increase to 30+ mph in the afternoon. If these winds arrive sooner fresh wind slabs will be forming on slopes being loaded with wind blown snow. 

    Watch for active wind loading. Shooting cracks and snow that feels stiff underneath you are good indicators you are traveling on a wind slab. Cornices also grew overnight. On Sunday Wendy saw two natural cornices fall off the Magnum ridgeline. They will be even easier to trigger from a person so give them a lot of room on ridges.  

    Loose snow avalanches: Look out for dry loose avalanches in steep terrain where the snow is dry. Wet loose avalanches are also likely below 2,000’ where the snow is warm and wet. 

    Glide Avalanches: Glide cracks are still opening and could release into a glide avalanche at any time. Look for these on slopes above you and try to avoid them whenever possible.

    There were no natural avalanches in Tincan Common but lots of wind transport going on.

    Photo: John Sykes

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