Avalanche forecast

South Rockies

Mar 7 – 9, 2012Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–5
    Wind slabs fueled by gusty NW winds and new snow are an issue in wind exposed terrain.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–6
    Avalanches failing on a weak layer buried around mid-February have the potential to be large and destructive.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    New snow should bond well to the old snow surface, but be careful with convex rollers and unsupported slopes where the chances of triggering an avalanche are increased.

Confidence

Fair - Intensity of incoming weather is uncertain on Friday

Weather Forecast

Thursday: A ridge of high pressure will bring dry and bright conditions with generally light northwesterly winds and freezing levels rising to around 2000m. Friday: A Pacific frontal system will bring around 5 mm precipitation, which may fall as a mix of snow and rain. Freezing levels will be up to 2000m. Winds will be strong southwesterly. Saturday: Another frontal system moves through late in the day, bringing further light to moderate amounts of precipitation, cooler temperatures and strong winds.

Avalanche Summary

On Wednesday, a size 2 avalanches was reported from around 2300 m in the South York Creek area on an east aspect. Limited amounts of sluffing from solar activity was also noted. On Tuesday there was a report of a snowmobile-triggered avalanche, details are limited at this time. On Tuesday, professionals were successfully & intentionally triggering small avalanches during control work in the new snow.

Snowpack Summary

20 to 50 cm of recent storm snow reported from the regions. Feb. 09 surface hoar is now down between 40 & 100cm. The depth varies throughout the region. This weak layer continue to perform and snowpack tests continue to show sudden moderate failures on this interface. The weekend's strong winds and mild temperatures formed the upper snowpack into a more cohesive slab. Lingering concern remains for basal facets, particularly in shallower snowpack areas with steep, rocky start zones. I suspect windslabs are developing with the forecast wind and recent snow.

Regions covered