Avalanche forecast

Kootenay Boundary

Mar 7 – 8, 2013Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–6
    The 80 cm deep surface hoar/sun crust weak layer could be triggered by a cornice fall or an avalanche stepping down from the storm snow. Be aware of the sun and warmth weakening the snowpack and cornices on Friday afternoon and Saturday.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
      Up to 30 cm of recent snow is sitting on a melt freeze crust and has formed touchy storm slabs. It is also sluffing easily on steep slopes.

Confidence

Good

Weather Forecast

Thursday night and Friday: Precipitation associated with the upper low will ease off and give place to a light, cool and dry northerly flow. Light amounts are expected on Friday with light North winds and temperatures around -6 C in the alpine. Overcast skies starting to clear in the afternoon. Freezing levels will rise to 1400 m. tomorrow.Saturday: High pressure brings dry conditions, mainly clear skies, light NW winds and freezing level rising up to 1200 m. in the afternoon. Sunday: A frontal system approaches from the North coast Saturday night weakening as it hits the interior but could leave some light precipitation amounts, slightly cooler temperatures and winds switching from the SW.

Avalanche Summary

Some sluffing in steep terrain was reported. No other recent avalanches was reported.

Snowpack Summary

Around 18 cm (30 cm in the Western part of the region) of new snow fell on top of the recent storm snow above 2000 m., on a 1-3 cm thick melt freeze crust below 2000 m. and on a sun crust on S facing slopes.  This new snow is sluffing easily in steep terrain. Soft slabs were also formed on lee terrain from Easterly winds.  In much of the region, up to 80 cm snow overlies fairly well preserved surface hoar and sun crust. This interface is still producing sudden collapse results during snow tests.  A cornice fall or an avalanche in the storm snow could definitely trigger this deeper instability. The sun and warming temperatures tomorrow afternoon and Saturday will most likely weaken the snowpack and cornices especially on S facing slopes.A strong melt-freeze crust exists at 1700 m and below and is bridging deeper instabilities. 

Regions covered