Boletín de aludes

Kootenay Boundary

Jan 29 – 30, 2016Avalanche Canada
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Archivado · caducó 11 years ago

Peligro de aludes

Sun
Mon
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Lo esencial

A cooling trend with light snow falls will slowly drop the avalanche danger. The recent storm slab may need another day or two to settle and stabilise.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    3–5
    The persistent weak layer of surface hoar may continue to be triggered by large loads or small loads in shallow or weak areas.

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–3
    Buried layers of surface hoar and thin freezing drizzle crusts may be found within the storm slab. Triggering this storm slab has become less likely, but may be possible in areas that had less warming during the storm.

Confidence

High

Weather Forecast

Moderate westerly winds overnight with light snow and freezing levels dropping down to valley bottoms. Expect 5-8 cm by Saturday morning. Moderate westerly winds continuing on Saturday with some periods of broken skies and freezing levels staying below 800 metres. Light southwest winds on Sunday and Monday with some periods of flurries and temperatures around -10 in the alpine.

Avalanche Summary

Natural storm slab avalanches were reported on Thursday from the Kootenay Pass area during the warm faze of the storm. I suspect that natural activity has stopped, but the persistent weak layer may still be triggered by large loads like a group of sledders or skiers re-grouping.

Snowpack Summary

Warm temperatures settled the recent storm snow, and then a cooling trend tightened the existing storm slab which sits over buried surface hoar in many parts of the region. This surface hoar layer appears to be down 30-40cm and a second more recently buried layer of surface hoar may also be found down around 10-20cm. A thin melt-freeze crust may also be found buried in the upper snowpack but does not seem to be creating an instability. Recently strong south to southwest winds have likely formed new wind slabs in leeward features in the alpine. At lower elevations, warm temperatures and rain have likely melted the surface and a melt-freeze crust is expected to form with the cooling trend. The recently destructive early January surface layer is down 60-100cm and is most prominent on all aspects at treeline and below. It is getting harder to trigger this layer but it is still reactive in snowpack tests suggesting that if you are able to trigger it, the layer is capable of wide propagations and large destructive avalanches.

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