Avalanche forecast

South Columbia

Apr 16 – 17, 2013Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Northern parts of the region may have similar conditions to the North Columbia and Glacier National Park regions. Check these bulletins to get the complete picture.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Wind slabs exist on a variety of aspects at treeline and above. Wind has also formed very large and potentially unstable cornices.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–6
    A weak interface buried down about 60-120 cm has been creating surprisingly large avalanches in neighbouring regions. Incremental loading by snow and wind may have brought the slab above this layer closer to its tipping point.

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Wednesday: Light snow. Moderate SW winds. Freezing level near 1500 m. Thursday: Light snow. Light to moderate SW winds. Freezing level near 1800 m. Friday: Moderate to heavy snow. Light SW winds. Freezing level near 1800 m.

Avalanche Summary

On Sunday, a naturally triggered size 2.5 slab failed on a buried crust. Numerous small loose dry avalanches were also observed. In neighbouring Glacier National Park, skiers triggered a size 3 slab on a buried crust on an east aspect in the alpine on Monday. The slab above this interface may be reaching tipping point with incremental loading from snow and wind.

Snowpack Summary

Up to 40 cm recent storm snow has been shifted into variable wind slabs at treeline and above. In some areas, easterly winds have led to wind slabs on different slopes than you might usually expect. Cornices are very large and potentially destructive.A weak interface down about 60-120 cm consists of a crust on solar aspects, and surface hoar on high-elevation northerly aspects. Recent very large avalanches in neighbouring regions to the north failed on this interface. The slab above this interface may be reaching tipping point with incremental loading from snow and wind. Periods of warming or solar radiation may increase the reactivity of cornices and storm slabs. 

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