Avalanche forecast

Purcells

Dec 30 – 31, 2014Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Avalanche danger is expected to remain at Considerable during the forecast cold and clear weather for the end of the year.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    The mid-December crust and surface hoar layer is now buried between 30-60 cm and continues to be a concern for triggering by light additional loads like a skier/rider.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    3–6
    The deeply buried crust/facet layer that developed in November continues to be a concern for triggering from large loads like re-grouping, or from shallow weak spots around boulders and small trees.

Confidence

Fair

Weather Forecast

Clear and cold overnight with alpine temperatures dropping to about -25 and moderate Northeast winds. Winds becoming light Northwest during the day on Tuesday and alpine temperatures rising up to about -14 under clear skies. Cold and clear with light Westerly winds on Wednesday. Increasing cloud on Thursday afternoon with a chance of light snow in the evening.

Avalanche Summary

No natural avalanches reported. Explosives control work resulted in avalanches up to size 1.5 that appear to have run on the mid-December surface hoar that is buried down 40-60 cm.

Snowpack Summary

Some areas may have a thin layer of surface hoar that was buried on December 27th and now has about 5-10 cm of light dry snow above. The slab above the persistent weak layer of surface hoar and crust that was buried in mid-December is now 40-60 cm thick and gives mostly sudden planar results in snow profile tests when moderate forces are applied. The persistent slab problem is widespread across the region and is not expected to improve it's bonding properties during the forecast dry and cold weather. Shallow snowpack areas continue to have concerns for a deeper early season crust/facet layer down more than a metre that may collapse under large loads or from weak trigger spots around exposed rocks and/or trees.

Regions covered