Avalanche forecast

South Columbia

Mar 5 – 6, 2013Avalanche Canada
View on map
Archived · expired 14 years ago

Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
Open full map

Highlights

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    4–7
    There is a weak layer of buried surface hoar down about 100-150 cms that may be triggered by large loads like re-grouping, cornice fall, or smaller avalanches in motion. Strong solar radiation may initiate this layer where it sits on a crust.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–6
    The storm snow is settling and bonding, but may continue to be triggered by human activity. Periods of strong solar radiation may cause a cycle of storm snow releases on Southerly aspects.

Weather Forecast

Overnight and Wednesday: Mostly cloudy in the South with flurries beginning overnight. The South of the region is forecast to receive up to 10 cms of snow due to a weak low pressure system moving along the U.S. border. The North of the region is expected to remain mostly clear and dry.Thursday: Mostly sunny and dry in the North. Lingering cloud and convective flurries in the South with moderate Northwest winds.Friday: Mostly sunny and dry with alpine temperatures about -8.0 and light Northwest winds.

Avalanche Summary

Natural avalanches up to size 3.0 continue to be reported failing on the February 12th surface hoar that is buried down about 120-150 cms. Some smaller avalanches size 2.0 were reported failing down about 40 cms in the storm snow. A couple of natural cornice falls also occurred.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Thursday

Snowpack Summary

The storm snow is expected to settle and bond to the old surface over the next few days. A crust has formed up to about 1800 metres where the recent warm storm had turned to rain. In the alpine there may be a weak layer in the storm snow that was developed during a temperature change in the middle of the storm. Below the storm snow lies a highly reactive weak layer of surface hoar (and/or a crust) which was buried on February 12th. Deeper persistent weak layers from early February and late January continue to show planar failures when moderate to hard forces are applied in snow pack tests. In particular, in the Monashees, a rain crust buried down 150 cm has been responsible for a couple of recent large, surprising avalanches.

Regions covered