Bollettino valanghe

Kootenay Boundary

Mar 19 – 20, 2012Avalanche Canada
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Archiviato · scaduto 15 years ago

Pericolo valanghe

Wed
Thu
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Danger ratings are based on 20-25cm snow accumulation and very strong winds on Tuesday. It could be slightly lower if the system is a little less intense than forecast.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1–4
    Fresh wind slabs are forming on exposed lee and cross-loaded features in response to new snow and loading by SW winds.

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–6
    Cornices are very large and may fail with daytime warming, especially with sunny breaks. There is potential for triggering deep slabs on underlying slopes.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    2–7
    The deep nature of the mid-February surface hoar layer makes potential avalanches triggered on this layer large and destructive. Avoid thin snowpack areas where triggering is more likely.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

A frontal system will spread light to locally moderate snowfall tonight and through Tuesday. Some areas could see up to 20cm. Winds are expected to be strong from the southwest. Wednesday should be another unsettled convective day with generally 3-5cm and lighter winds. Another system should spread light or moderate snowfall on Thursday, but the track of this system is still a little uncertain. The daytime freezing level should hover around 1000m each day.

Avalanche Summary

One recent Size 3 avalanche was observed in the north end of the region last weekend. This avalanche was suspected to have released on the early February surface hoar layer. There was also a report of a Size 2 avalanche remotely triggered by a snowcat in rocky and variable terrain on a north aspect. This avalanche occurred just outside the region to the north. Otherwise avalanche activity has been limited to Size 1 skier triggered wind slabs or loose snow sluffs.

Snowpack Summary

An additional 20cm of new snow brings the total storm snow amount to around 100cm in most areas. Several resistant shears have been noted in the storm snow. A sun crust on southern aspects and a spotty 2-6mm surface hoar on north and east aspects is down around 60-90cm. Below that, the more significant early February surface hoar is down 100-160cm. Snowpack tests show moderate to hard forces generating sudden planar shears on this layer. A melt-freeze crust, down 20-30cm, below 1800m provides some bridging to the layers below. Below the early February surface hoar layer, the snowpack is strong in most places. Cornices are very large and would act as a significant trigger for all the layers mentioned above if they drop.

Regioni coperte