Avalanche forecast

Purcells

Dec 12 – 13, 2012Avalanche Canada
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Archived · expired 14 years ago

Avalanche danger

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

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Watch for pockets of windslabs under ridges especially in the alpine. They could have the potential to propagate widely on large planar slopes.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    There are two layers of buried surface hoar in the region down 50 cm and down 30 cm. Professionals are still concerned about these layers in unsupported terrain.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    Typical trigger points include thin rocky areas on steep unsupported slopes. Step-down avalanches are also a concern.

Confidence

Fair - Due to limited field observations

Weather Forecast

A weak system will cross the region in the evening Thursday bringing flurries and light North West winds becoming moderate from the South West later.  Temperatures will stay cool for the entire period. Similar conditions are expected for Friday and Saturday except for the winds turning back and forth from the North West to South West and staying light for the rest of the period.

Avalanche Summary

No new natural or skier triggered avalanche was reported recently except for explosive results up to size 2 that ran on West and North West aspects down 40-80 cm on facets. Check out this avalanche report from the Kicking Horse backcountry.from December 10th.

Snowpack Summary

The 5-10 cm of new snow that fell in the past couple days is sitting on the older storm snow and is continuing to settle. Some isolated windslabs exist in the alpine and at treeline on Easterly aspects and on cross loaded features. This loads 2 surface hoar and/or facet layers that were buried at mid November and then, at the end of November. Except for explosive results, recent snowpack tests gave no significant results on these weaknesses located consecutively around 50 cm and 100 cm below the surface of the snowpack. Near the base of the snowpack is the early November crust/facet deep persistent weakness. It would be possible to trigger if you hit the right spot, like a thinner snowpack area on a slope with smooth ground cover. 

Regions covered