Avalanche forecast

South Rockies

Dec 30 – 31, 2014Avalanche Canada
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Avalanche danger

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

The Special Avalanche Warning has been extended until January 4th. Stay vigilant and be cautious in your terrain selection. Touchy persistent slabs and wind slabs exist.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Between 15 and 30 cm of low-density snow has been transported by strong southwest winds into hard wind slabs.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–4
    A crust which formed in December should remain on your radar. Not much is known about its distribution in the South Rockies. However, in neighboring regions it has produced large avalanches. Dig down and test weak layers before committing to a line.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Arctic air dominates the province. The weather remains benign with cold and mostly clear skies through Wednesday. High level moisture is developing on Thursday bringing some cloud cover. Alpine temperatures will be steady near -15 accompanied by moderate NW winds. On Friday things begin to change, however; at this point confidence is poor in model solutions with precipitation amounts.

Avalanche Summary

On Monday, no new avalanches were reported in the South Rockies. However, wind slabs to size 2 were observed in the Lizard range. One was a natural avalanche and the other was skier controlled. With forecast northwest winds, we could see a new round of wind slab activity as surface snow gets redistributed onto south-facing slopes.

Snowpack Summary

Up to 30cm of low-density snow exists on the surface. In the alpine and at treeline, strong to locally extreme winds have transported this snow into stiff and reactive wind slabs in exposed lee areas. Up to 70 cm below the surface (more in wind affected areas) you may find a crust which formed in December. The crust, which may have surface hoar on top of it, may extend into the alpine to at least 2100 m. Where the crust exists, it may be bridging triggers from penetrating to deeper persistent weaknesses. However, on high alpine slopes above where the rain crust formed, or in areas where rain didn't occur, deeply buried facets may still be susceptible to triggering especially in thinner snowpack areas.

Regions covered