Avalanche forecast

Kootenay Boundary

Jan 26 – 27, 2012Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    New snow and strong winds have set up touchy wind slabs on the lee of exposed features and slopes. Loading may have occurred lower down on slopes due to strong winds.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–5
    Dense new snow now sits on previous low density snow. With recent loading, this interface may become reactive, and storm slab avalanches may occur.

Confidence

Fair - Due to variable weather conditions

Weather Forecast

Friday: Mostly clear / light to moderate southwest winds / freezing level at 300mSaturday: Mostly clear with increasing cloud and snowfall in the late afternoon / moderate northwest winds becoming strong from the west / freezing level at 700mSunday: moderate snowfall / moderate westerly winds / freezing level rising to 1300m

Avalanche Summary

Numerous size 1 to size 2 natural and explosive-controlled avalanches were reported in the region in the last 24 hours (mostly on north aspects above 2000m).

Snowpack Summary

On wednesday evening about 8cm of snow fell in the region adding to the 15-25 cm of snow that fell on tuesday. Tuesday's system was accompanied by strong to extreme winds from the southerly quarter producing reactive new wind slabs which are now the primary concern in the snowpack.Over last weekend up to 35cms of new snow fell. This new snow came in denser that the previous cold storm. This has been a recipe for continued storm slab instabilities as these slabs are reported to be quite reactive due to their poor bond on the cold snow interface below.I would suspect that time is helping to strengthen the recent storm and windslab problems, but I wouldn't write them off just yet as triggering is still a real possibility. Layers of concern deeper in the snowpack include a surface hoar/facet layer from mid-December and weak basal facets at the base of the snowpack in shallow snow areas. These layers have become less of a concern in the vast majority of locations. Last Saturday the mid- December layer is thought to have failed in several large avalanches that occurred in the Bonnington Range. This is a lingering layer of concern that reflects low probability but high consequence. Snowpack depths in the region are around 240 cm.

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