Avalanche forecast

South Columbia

Mar 12, 2017Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
4 · High
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Snow, wind and warming will keep storm slabs touchy. When you add the prospect of cornice triggers, the likelihood of large persistent slabs is expected to increase.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–4
    Various persistent weaknesses strewn throughout the snowpack create the potential for large step-down avalanches. Warming is expected to increase the likelihood of these large avalanches, especially with cornice-fall triggers.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Weaknesses within the recent storm snow are susceptible to human triggering. These storm slabs are particularly deep and touchy on slopes loaded by southerly winds and have the potential to step down to deeper persistent weaknesses.

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

We'll have light to moderate snowfall amounts through to Monday morning, and then it starts to warm up Monday afternoon. SUNDAY: Cloudy with another 10-15cm of fresh snow by morning and continued light flurries throughout the day accompanied by moderate SW winds. Alpine temperatures hovering around -5 C.MONDAY: Cloudy with another 5-10cm by morning accompanied by moderate to strong SW winds and freezing levels rising as high as 1800m.TUESDAY: Scattered flurries (3-5cm) with moderate southerly winds. Freezing levels remain near 1900m.

Avalanche Summary

A widespread wind and storm slab avalanche cycle to Size 2.5 was reported on Friday at all elevations and aspects, particularly in the alpine.

Snowpack Summary

Around 25-40cm of fresh snow has fallen over the past two days (with moderate southerly winds) and has added to the 60-100cm of settled storm snow from the past week. Touchy storm slabs can be found at all elevations with weaknesses within and under this recent snow.All this new snow is bonding slowly to faceted snow as well as isolated small surface hoar in sheltered areas and a thin sun crust on steep southerly aspects. The persistent weakness buried mid-February is now down 90-135 cm, and is composed of a thick rain crust as high as about 1800 m, sun crusts on steep southerly aspects, and spotty surface hoar on shaded aspects. This and deeper persistent weaknesses have seen a recent increase in more sudden snowpack test results and has been identified as a failure plane in a number of recent avalanches.The mid and lower snowpack are well settled and stable in deeper snowpack areas, but may be weak and faceted in shallow areas.

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