Bollettino valanghe

South Columbia

Mar 31 – Apr 1, 2016Avalanche Canada
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Archiviato · scaduto 11 years ago

Pericolo valanghe

Sat
Sun
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
Apri la mappa completa

In sintesi

Special Public Avalanche Warning for this region. Continued very warm temperatures with little overnight freeze coupled with strong solar radiation will increase the avalanche danger to HIGH in the alpine during the hottest part of the day.

Problemi valanghivi

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    2–5
    Continued high freezing levels and very warm daytime temperatures are very likely to result in natural cornice falls. Large cornice falls may trigger buried weak layers resulting in very large avalanches.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    3–6
    Continued warm and sunny weather may add enough heat to the snowpack to “wake-up” persistent weak layers buried in the snowpack. Rapid warming of the winter snowpack can result in deeply buried weak layers propagating very large avalanches.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely - Certain
    Dimensione
    1–4
    Forecast high freezing levels and very warm daytime temperatures may break down surface crusts early and result in loose wet avalanches from steep solar aspects. Wet slab avalanches are possible if loose snow propagates on a buried crust.

Confidence

High

Weather Forecast

A high pressure ridge continues to bring warm, sunny weather to this region. Freezing levels are expected to remain as high as 3000 m through Friday. On Saturday, a very minor low pressure system moves through, bringing cloud cover and possibly some flurries. Winds are expected to be moderate from the southwest and we should see a slight lowering of the freezing level to around 2500 m. On Sunday, expect a mix of sun and cloud and freezing levels around 2300 m.

Avalanche Summary

On Tuesday and Wednesday numerous solar-triggered loose wet avalanches were reported up to size 2.5. On Monday some recent storm slab avalanches were reported releasing from skier triggering up to size 1.0 on north aspects in the alpine. Some natural cornice activity was also reported up to size 2.5 from northeast and easterly aspects in the alpine. Forecast very warm temperatures and high freezing levels are expected to increase natural cornice activity, and may trigger the buried persistent weak layers.

Snowpack Summary

New surface crusts have formed at all elevations on solar aspects, and on all but high alpine shaded aspects. Some areas have reported a new layer of surface hoar growing in high sheltered alpine locations above 2300 metres. Approximately 40-50 cm of settled storm snow sits on a melt-freeze crust buried on Mar. 22. The late February persistent weak layer is an aspect dependant mix of surface hoar, facets and/or a thick crust down around 60-110 cm below the snow surface. Commercial operators continue to see hard sudden planar results in snowpack tests, which suggests that wide fracture propagations are possible. Cornices continue to be described as large and fragile. Expect loose wet avalanches and natural cornice falls with strong solar radiation and significant warming this week. Forecast warming may trigger very large slab avalanches on one of the buried crusts or associated weak layers.

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