Avalanche forecast

Purcells

Dec 2 – 3, 2012Avalanche Canada
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Archived · expired 14 years ago

Avalanche danger

Tue
Wed
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    Two problem layers exist: A surface hoar layer 30 - 60 cm below the snow surface and the early Nov. crust near the ground. It may be possible for a rider to trigger these weak layers, especially in areas where the snowpack is thin and/or rocky.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    The storm slab should settle and bond over the next few days. Pockets of wind slab in the alpine may continue to react from the additional load of skiers and riders.

Confidence

Poor - Timing, track, or intensity of incoming weather is uncertain on Tuesday

Weather Forecast

Overnight and Monday: Precipitation is expected to be light overnight, and there may be some sunny breaks during the day Monday. Strong gusty west winds overnight should decrease to moderate SW during the day.Tuesday: The next Pacific system is expected to bring 10-15 mm during the day to the western parts of the region. The eastern parts of the region may only see 2-5 mm. Strong SE winds at the beginning of the storm should clock to the SW and continue strong with very strong gusts.Wednesday: Precipitation amounts should be light in the wake of the storm and freezing levels should drop down to near the valley bottom.

Avalanche Summary

Some avalanches up to size 1.0 have been reported from explosive control, releasing wind slabs down about 20 cms on NE aspects.

Snowpack Summary

Report of a 10 cm stubborn wind slab on NE aspects in the alpine. Variable reports of a surface hoar layer that developed last week and was buried on the 28th; releases are likely on this layer if you have it in your area. There is a surface hoar layer that developed during mid-november was reported to be active last week, but has not been reactive during the recent storm. There is a rain crust near the ground that we're calling the early November crust. There are some facets below it, or it may appear as a sandwich of crusts and facets, but it's been reported  as unreactive at this time. There is still a sharp transition in snow depth from treeline to below treeline making back-country travel challenging under 1300 m in elevation.

Regions covered