Avalanche forecast

Northwest Coastal

Dec 11 – 12, 2015Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Conditions below tree-line vary greatly with elevation. Many areas are still below the threshold for avalanches but buried surface hoar may be present as you approach tree-line.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Moderate to strong north through east winds have created soft slabs in lee features both at ridge-top and on cross loaded slopes.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    Human triggered avalanches are still possible, especially on North facing terrain at, and just below tree-line due to a layer of buried surface hoar.

Confidence

Low - Due to the number of field observations

Weather Forecast

SATURDAY: Flurries with up to 10cm localized to costal regions, light southwest winds, freezing level at 500m SUNDAY: mainly clear, moderate south east winds, freezing level at valley floor 1000m. MONDAY: mainly clear with flurries possible in the afternoon, light northwest winds, freezing level at valley floor.

Avalanche Summary

Widespread avalanche activity was reported through recent storm, with several avalanche releasing on the layer of surface hoar now buried between 70cm and 1m deep. Natural activity on this layer has slowed since the storm ended on Thursday. Explosive avalanche control around Shames produced smaller storm slab avalanches that released on mid-storm instabilities under larger triggers.

Snowpack Summary

Up to a meter of settled snow fell in the last week which may be sitting upon a layer of buried surface hoar. This layer has the potential for remote triggering and wide propagations. It is likely to be lurking on sheltered north facing slopes at or just below tree-line although it has been spotted well into the alpine in Bear Pass. Strong north through easterly winds overnight on Thursday have reverse loaded lee features. Low, below tree-line elevations may still be bellow threshold for avalanches in many places.

Regions covered