Boletín de aludes

South Columbia

Dec 31, 2011 – Jan 1, 2012Avalanche Canada
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Archivado · caducó 15 years ago

Peligro de aludes

Mon
Tue
Alta montaña
4 · Fuerte
Límite del bosque
3 · Notable
Bajo el límite
3 · Notable
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Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely - Very Likely
    Tamaño
    1–5
    Winds continue to redistribute storm snow into fresh wind slabs. I'd be suspect of any open area, even below treeline. Once moving, a wind slab could easily step down and trigger a large avalanche.

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    4–7
    A cohesive slab sits over a touchy surface hoar weakness buried in mid-December. Avalanches on this layer will be large, destructive and may fracture across surprisingly far distances.

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

A ridge of high pressure drifts into the area Saturday evening driving overnight temperatures into the mid minus teens. On Sunday morning high clouds steam into the region ahead of the approaching mass of warm air. Light precipitation should begin after lunch, but I'm only expecting 5 or so for the day. The bigger story with the warm front is the rise in freezing levels which could go as high as 2000 m. Winds build to moderate/strong values out of the SW Sunday. A weak cold front affects the area Monday afternoon bringing another shot of light precipitation & lowering temps/freezing levels.

Avalanche Summary

Many small natural avalanches confined to the new snow have been reported from the region. While important to note, the big story is the continued activity on the mid December surface hoar/facet/crust layer. The bottom line is that this layer continues to be very sensitive to skiers & sledders. There are numerous reports coming in of remote triggering, that is, people triggering avalanches from far away. It's also significant that avalanches failing on this layer are being reported in areas we sometimes deem as "safe." Both natural and human triggered avalanches continue to be in issue on treed slopes.

Snowpack Summary

Around 100cm of total storm snow has fallen in the region since Christmas. Winds have redistributed the storm snow into wind slabs that are quite widespread; you can find them at and above treeline in wind exposed locations. Even open areas below treeline are suspect for wind affected snow. A surface hoar/facet/crust interface (persistent weakness aka PWL) from mid-December is buried anywhere from 80-100cm deep & has been quite reactive making for touchy avalanche conditions. Below this lies a well consolidated and strong lower snowpack.

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