Avalanche forecast

Banff Yoho Kootenay

Dec 19 – 20, 2013Parks Canada
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Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
1 · Low
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Highlights

Basal weaknesses are waking up with the added snow load. Avalanche control today produced large, destructive avalanches.  Use caution in avalanche terrain!

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    40-60 cm of storm snow has created touchy wind and storm slabs which are easily triggered and will likely step down to the basal weak layers.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    The deep persistent weak layers (facets, depth hoar, and october rain crust) are waking up with the added load.  Triggering this layer is likely and will result in large, destructive avalanches as seen in avalanche control work today.

Weather Forecast

Cooling temps (-15 to -25) and clearing skies for Thursday.  Possibly some light precipitation on Friday/ Saturday.  Light SW/W winds throughout the period

Snowpack Summary

Another 10-20 cm of new snow today brings the storm snow total to 40-60 cm. Moderate to strong winds have created touchy windslabs in the alpine and at treeline.  Basal facets, depth hoar and the october rain crust are prominent at the base of the snowpack.

Avalanche Summary

Avalanche control work today on the Sunshine road produced large avalanches (size 2.5-3) on 6 of 9 shots. These avalanches appeared to initiate in the storm snow and step down to the October crust.  Similar reports from the Sunshine avalanche control team and a report of a size 2.5 natural near Bow Summit indicate widespread instability.

Confidence

Regions covered