Boletín de aludes

Waterton Lakes

Jan 13 – 16, 2015Parks Canada
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Archivado · caducó 12 years ago

Peligro de aludes

Tue
Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Lo esencial

With surface faceting softening the upper snowpack, some surprisingly good skiing can be found if you can avoid surface crusts.  Remember to keep terrain choices conservative as triggering the Persistent Weak Layer remains a possibility for travelers

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2
    Windslabs can easily be found in most open areas over low density snow. In isolated locations these are significant: hard and thick. Test these surface slabs often with your ski poles and modify your route to manage your exposure should they fail.

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely - Possible
    Tamaño
    1–3
    Continue to watch for this layer which has proven to be extremely variable. Areas where these slabs are thin should raise added concern.

Weather Forecast

We will remain under the influence of the SW flow for the period with warm moist air trying to override the cooler air on the prairies. Clouds and trace precip are likely near the divide. By Friday a warm front associated with a low approaching the coast will bring an increase in the freezing level, stronger winds and potentially some precipitation

Snowpack Summary

Generally, with the current drought conditions the upper snowpack is faceting. Windslabs overlying softer snow are the primary surface concern.  In the midpack, the Dec 13 crust is now 60 to 120cm deep and remains a serious concern as it produces planar shears within the facets above the crust. Surface crusts affect ski quality.

Avalanche Summary

Despite seeing very little activity over the last few days we observed a significant slab about  40m wide, 80 to 100 cm deep on steep north facing cliffy terrain near ridge top. This slab likely failed on the Dec 13 persistent weak layer although it may have been triggered by a smaller slab and illustrates the need for care with this layer.

Confidence

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