Avalanche forecast

Purcells

Dec 19 – 20, 2015Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

New snow and strong winds on Sunday will keep the Avalanche Danger elevated. Watch for new wind slabs.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Even if new snow amounts are modest in your riding area, there's plenty of loose snow on the ground for redistribution by forecast strong winds on Sunday. Watch for new wind slab development at treeline and in the alpine.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–4
    A layer of buried surface hoar can be found between 1400m and 1800m. Use increased caution on steep roles on cut-blocks and in open glades below treeline.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Sunday

Weather Forecast

Between 5 and 15cm of new snow and strong to extreme southwest ridgetop winds are expected on Sunday. Continued light flurries and moderate southwest winds will persist for Monday and Tuesday. Freezing levels should sit at valley bottom for all 3 days. For a more detailed weather overview, check out our Mountain Weather Forecast at avalanche.ca/weather.

Avalanche Summary

Observations were limited on Saturday; however, an explosive-controlled size 2 wind slab was observed on a north-facing alpine slope. Continued strong winds and new snow will likely be the driver for continued wind slab avalanche activity over the next few days.

Snowpack Summary

Recently formed wind slabs can be found at treeline and in the alpine. Between 40 and 80cm below the surface you'll likely find a layer of weak buried surface hoar which is most prominent between 1400m and 1800m although it may extend higher in the mountains south of Invermere. Snow pit tests suggest that human triggering of this interface is becoming unlikely, although a release at this interface could be destructive in nature. Below this, the snowpack is thought to be mainly well settled.

Regions covered