Avalanche forecast

Purcells

Dec 28 – 29, 2014Avalanche Canada
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Avalanche danger

Tue
Wed
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
    Thin windslabs and recent storm slabs may be sitting on a weak layer of surface hoar and/or a crust. This problem may persist through the Holiday season.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    Shallow snowpack areas may continue to have concerns for deeply buried crusts with facets at the interface.  Large triggers like storm slab avalanches in motion may step down to near the ground where this problem exists.

Confidence

Fair

Weather Forecast

Gradually clearing overnight with light Northeast winds and alpine temperatures dropping down to about -22. Mostly clear and cold on Monday with light to moderate Northeast winds and alpine high temperatures around -20. Clear and cold on Tuesday with light Northwest winds. Continued clear and cold on Wednesday.

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