Avalanche forecast

Northwest Coastal

Nov 28 – 29, 2011Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    2–5
    New snow combined with strong winds have created dense wind slabs at and well below ridge top. Additional wind and snow will further exacerbate this problem.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–5
    Weaknesses may exist within storm snow; 25 - 150 cm in depth.

Confidence

Fair - Due to limited field observations

Weather Forecast

25 cm to 70 cm expected from 4pm Mon - 4pm Tue.

Avalanche Summary

Control work in the North on Bear Pass on Sunday produced numerous dry loose snow avalanches size 1 -2, 15-30 cm in depth on SW - S aspects. One Xh size 2.5: 50 w x 1200 L x 100-150cm depth. To the South, Shames reported a Na SL sz 3.0, E @1300 m. 250 w x 1700 long. Failing on Nov11-19 SH. Other control work produced results very similar to that in the North.

Snowpack Summary

Saturdays system dumped another 50-75cm in many areas. Sunday brought another 25 - 35cm to upper elevations. The snowpack depth near treeline is already around 300cm. Fluctuating freezing levels and varying precipitation intensity and wind throughout the recent storms has probably resulted in various weaknesses within upper snowpack. A buried surface hoar layer may be found down close to 100/150cm, but there is no recent information on the presence and sensitivity of this layer. The mid and lower snowpack is generally well settled/strong with an old rain crust near the ground.

Regions covered