Avalanche forecast

Cariboos

Dec 5 – 6, 2011Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–4
    Windslabs should be settling and becoming a bit more stubborn to trigger. Hard slabs in the alpine may propagate into large avalanches.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    Probability of triggering has decreased. Where it still exists, this layer may be capable of producing highly destructive, full depth avalanches. Reactivity may also increase if temperatures rise.

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

A fast moving cold front is forecast to produce some light precipitation combined with strong winds from the southwest early Tuesday. The freezing level should drop to valley bottom overnight and remain below treeline on Tuesday. However, warm air is forecast to stay in the alpine during the day. Wednesday and Thursday should be cooler and drier with freezing levels rising to 1500 metres during the day.

Avalanche Summary

No new avalanches observed. Limited old activity observed.

Snowpack Summary

Surface hoar has been forming over the last few clear and cold nights. Expect to find a sun-crust that has formed in the alpine on south through west aspects. I expect that the surface hoar will no longer be present on aspects that have developed the sun-crust. Wind slabs persist in the alpine and in large openings at treeline. The windslab has become less reactive to human triggers; however avalanches up to size 2.0 are still possible due to this problem. Some areas have a rain-crust below treeline from the 28th of November that has been buried by about 20 cms of snow. This rain-crust may be developing facets, and could become a layer of interest after it is buried by more of a load. There is still some concern associated with the early November buried surface hoar layer. This layer is buried down about 100-150 cms. Tests are showing that this layer is getting harder to release, and less likely to give clean and fast shears (Sudden Planar). If an avalanche does release on this layer, it is likely to be very large and destructive. Some areas also have a weak layer of facets at the base of the snowpack.

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