Boletín de aludes

Turnagain Pass and Girdwood

Chugach National Forest Avalanche Center
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Peligro de aludes

Wed
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó last year. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Strong southeast winds and 4 to 8" of snow will increase the chance of triggering an avalanche on a layer of buried surface hoar 1 to 3’ deep. This layer has been concerning above 1,500’ on all aspects and is responsible for many human triggered avalanches. Wind slabs will also be forming in upper elevations. As the avalanche danger increases we recommend making conservative decisions like avoiding traveling in or under steep slopes.

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SPECIAL ANNOUNCEMENTS:

Come find us at the Seattle Ridge motorized parking lot on Saturday, March 22 for our annual Turnagain Pass Avalanche Awareness Day! We will be there with Alaska Mining and Diving Supply and the Alaska Avalanche School to chat about avalanches and current conditions and to hang out with the good people of the southcentral Alaska winter community. AMDS will have demo snowmachines, and we’ll be holding down the grill and the fire pit. Stop by anytime from noon until 4:00 p.m. Details Here.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2–3

    Recent Avalanches: On Saturday there were two human triggered avalanches around a foot deep on the south end of Seattle Ridge near the Headwall and in Triangle Bowl. At least one of them was remotely triggered. A large avalanche was reported on the Seattle Headwall that was 1,000’ wide and 1 to 2’ deep, likely releasing on March 13 or 14.

    The incoming storm will make it easier to trigger a large avalanche on a layer of surface hoar buried 1 to 3’ deep. 4 to 8” of snow is expected accompanied with strong southeast winds gusting to 50 mph in the afternoon. Portage may receive almost 20” of snow. This will increase the chance of triggering a large avalanche on a layer of buried surface hoar above 1,500’ on all aspects. 

    Today is not the day to get on or under steep slopes. The simple reason is that this storm will add stress to this weak layer and that people are still triggering large avalanches. Many of these avalanches have been remotely triggered meaning that people have triggered avalanches above or adjacent to them from low angle slopes. Snow tests are unreliable because they can give stable results on the same slopes we are seeing avalanches. Slopes with tracks on them seem safe yet we are still seeing avalanches after multiple people have ridden the slope. On the non-motorized side we have not had a large human triggered avalanche in a week, the last one being on Eddies, BUT people have not been getting into steep terrain. It is likely that if they do, human triggered avalanche activity will increase. This is why we are asking people to dial it back. Even with mixed field information, large avalanches are still occurring. Rather than trying to outsmart this problem it is safer to enjoy soft snow in less consequential terrain away from steep overhead slopes. 

    Cornices will be growing all day increasing the chance they fall and trigger an avalanche above you. This is another reason why today is not the day to travel below steep slopes. If you cannot avoid them try to spend as little time under them as possible. 

    Glide Avalanches: Glide cracks will likely be hard to see today. They are still releasing as glide avalanches so try to avoid traveling under them. If you do encounter one, spend as little time underneath them as possible. 

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2

    Strong southeast winds will be actively blowing snow into fresh wind slabs. These could be 1 to 2’ deep and will be easy to trigger on wind loaded slopes in upper elevations. There is a chance in places where more snow falls that these could release as natural avalanches. The biggest concern is that triggering a wind slab avalanche could trigger a larger avalanche on the buried layer of surface hoar mentioned above. 

    Blowing snow, traveling on stiffer snow and seeing shooting cracks underneath you are bullseye clues you are traveling on a wind slab. Trying to find a place where a touchy wind slab and buried surface hoar do not exist will be very challenging today. Instead of trying to outsmart all these problems the safest option is to avoid steep wind loaded slopes. 

    Storm Snow Avalanches: The storm has already brought with it strong winds and new snow In some places snowfall may be deeper than others. 4 to 8” of snow may fall by the end of the day. Portage may recieve 20" new snow before the storm passes. If you find yourself in a blizzard where the snow is piling up it will be more likely to trigger an avalanche in the storm snow. 

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