Avalanche forecast

South Columbia

Jan 28 – 29, 2015Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low

Highlights

Avalanche danger will drop as the temperature continues to cool, however, a widespread melt-freeze crust will make for challenging riding.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    In areas where the snowpack is not capped by a supportive crust a layer of surface hoar buried 40 to 70 cm down may still be capable of producing large avalanches.
  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    A deeper layer of surface hoar is still producing the occasional large avalanche given a large enough trigger in the right spot. It is especially a concern on open slopes around treeline.

Confidence

Fair

Weather Forecast

A ridge of high pressure will prevail through until Saturday over the southern half of BC, leading to mainly sunny skies in the mountains with extensive low cloud in the valleys. Freezing levels may rise to 1500m during the day but will return to valley bottom overnight. Winds will be mainly light from the west.

Avalanche Summary

As the temperature drops I expect that avalanche activity will slow down. The recent snow, rain, and wind were a great test of buried persistent weaknesses in the snowpack and resulted in a widespread avalanche cycle. The mid-January surface hoar layer was responsible for the majority of the recent avalanche activity although there have been reports from the Selkirks of occasional releases to ground and on the mid December layer.

Snowpack Summary

I suspect that freezing levels rose to between 2400 and 2800m during the recent warm spell and that rain saturated the upper snowpack. Above this elevation the surface is heavily wind effected. A breakable crust already exists in the alpine and as the freezing level continue to drop a widespread melt freeze crust is forming on all aspects and elevations. Reports indicate that riding conditions at lower elevations range for challenging to desperate. The mid-January surface hoar remains a concern and can be found down between 30 and 80 cm, however, I suspect that it may have been destroyed at lower elevations. The midpack is broken by the mid-December surface hoar layer that is now 80 to 140cm below the surface.

Regions covered