Avalanche forecast

South Columbia

Mar 13 – 14, 2013Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

High freezing levels, moist snow, and strong winds will result in High Avalanche Danger at all elevations.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    4–7
    A weak layer of buried surface hoar down about 100-150 cm may be triggered by the load of new storm snow and wind.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–6
    Another pulse of heavy precipitation and continued warm temperatures is expected to add to the already moist and reactive storm slab. Storm slabs are expected to release naturally or be triggered from adjacent terrain.

Confidence

Fair - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

Overnight and Thursday: The next strong pulse of moisture is forecast for Wednesday night, and is expected to continue during the day on Thursday. 10-20 cms overnight and another 20-30 cms during the day. Warm temperatures are not expected to lower overnight, and freezing levels should remain at about 1600 metres.Friday: The Pacific moisture feed should end by late morning as the Low pressure system tracks Northward up the coast. Temperatures and freezing levels should begin to lower. Chance of some broken skies in the afternoon.Saturday: Continued unsettled weather in the wake of the storm. Poor confidence in weather scenarios for Saturday.

Avalanche Summary

A widespread cycle of natural avalanches up to size 2.0 was reported early in the storm before poor visibility and travel conditions limited observations.

Snowpack Summary

Another pulse of heavy precipitation is forecast to add to the already moist heavy storm slab that is covering a widespread layer of surface hoar (March 10th layer) that developed during the recent clear weather. Strong Westerly winds during the storm have developed thick wind slabs at higher elevations where the snow was drier and easily transported. Sun crusts also developed during the clear weather on solar aspects up to about 1800 metres. Some areas had strong winds before the surface hoar was buried, so the distribution may be specific to sheltered and shaded terrain features. There is still concern for the buried weak layer of surface hoar from February 12th that is now down more than a metre in most places. The forecast new load of snow and wind may overload this deeply buried weak layer in areas that did not slide after the last storm.

Regions covered