Avalanche forecast

Kootenay Boundary

Apr 10 – 11, 2017Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

There are lingering wind slabs on northeast aspects, and watch for the influence of the sun on southern aspects.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Wind slabs have recently formed in north facing terrain at higher elevations and are expected to remain reactive to human triggering.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    Watch for loose wet avalanches on steep south-facing slopes when the sun comes out.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Tuesday: Flurries. Mostly calm winds. Freezing level around 1600 m. Wednesday: Dry with sunshine in the morning, becoming cloudy with some flurries in the afternoon. Winds 20-30 km/h from the southeast. Freezing level around 1600 m. Thursday: 15-20 cm new snow overnight Wednesday and into Thursday. Winds light southeasterly. Freezing level around 1500 m.

Avalanche Summary

On Monday, a size 2 avalanche was ski cut in recent storm snow in the Monashees. A similar sized avalanche was also naturally triggered. On Saturday there was an accidentally triggered size 2 wind slab reported in the Valhallas. I think this kind of shallow wind slab in alpine terrain is representative of a lingering wind slab concern: localized pockets, lee and cross-loaded features, around 20 to 30 cm thick. Although not in this region, Saturday's fatal avalanche accident on Mt. Harvey (South Coast Mountains) highlights several of the risks posed by cornices: multi-ton snow boulders serve as large triggers potentially releasing big avalanches on the slopes below, and they can break well back making for tricky travel along ridge crests.

Snowpack Summary

In exposed high elevation terrain, recent moderate southerly winds and new snowfall have formed wind slabs in leeward features. At lower elevations and on sun exposed slopes, there is likely moist or wet snow sitting on top of several well bonded crust layers in the upper snowpack.

Regions covered