Boletín de aludes

Central Cascades

Central Oregon Avalanche Center
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Peligro de aludes

Sun
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Triggering an avalanche in wind deposited snow will be likely on Saturday. Moderate to strong southwest and south winds will be loading northerly and east facing lee slopes near and above treeline. Ease into steep terrain, evaluate slopes for windloading, and if you see signs of unstable snow such as cracking or previous avalanches increase your safety margin by moving to lower angle options below 30 degrees.

Problemas de aludes

  • Wind Slabs

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

    With moderate to strong winds, wind slabs can form in weird places and in some cases not at all. Sometimes the blowing snow blasts into the atmosphere never to be seen again, and in other cases it can create deep wind slabs on certain terrain features. Nature can be unpredictable, but we can look for where blowing snow is ending up and look for signs of wind slab formation.

    Wind slabs typically form below ridge tops, high points, and terrain features that catch blowing snow. If you can judge that a slope has not been wind loaded, then a wind slab is not a problem.

    Watch for signs of blowing snow to indicate slopes are becoming loaded. Look for visual clues on the snow surface, such as pillowy deposits and wavy or ripply surface texture, to let you know if previous wind transport has occured. Wind deposited snow can be many times deeper than the snow the storm has dropped out of the sky.

    As drifts become deeper, resulting avalanches can become larger. Ease into terrain by checking out the wind loading on lower angle slopes. Monitor the depth of wind slabs and look for signs of unstable snow.

     

     

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    New snow is stacking up and with the air temperature rising to the upper 20's on Saturday, the new snow could exhibit slab characteristics. Think steep, rolling, and unsupported terrain with this one. Be cautious around steep features where a possible runout leads into trees, gully features or other terrain traps.

    Storm slabs failing on buried surface hoar may run farther and wider than they normally would.

Avalanche Discussion

On Friday, the buried surface hoar that was previously reported was found to be inactive. It was not producing alarming results in snowpack testing, at least at one location (east and northeast aspect, below treeline). It is a big area and it could be more or less active throughout the Central Cascades zone. I think it is too early to write it off and the COAC team will be checking it out in the coming days. Digging into the snowpack and doing some evaulation could be worth the time before dropping into steep and committing terain. 

Always be aware of newly formed cornices that are hanging over steep slopes. They can be fragile and break off at the worst time; ie when somebody steps out onto the diving board of snow hanging over a slope. 

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