Avalanche forecast

Kootenay Boundary

Mar 6, 2018Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

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

Buried weak layers sit beneath the new snow and have shown signs of being reactive to human triggers. Approach steep and convex terrain very cautiously.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5
    A few weak layers exist 50-100 cm below the surface and include sun crusts on south-facing terrain and surface hoar on north-facing terrain. They have been reactive to skiers and produced some concerning results in snowpack tests.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Storm snow from the past week may still be reactive to human triggers, especially in areas like the Rossland area that received up to 80 cm of snow. Triggering is most likely near ridge crests and around mid-slope features like convexities.

Confidence

High -

Weather Forecast

TUESDAY: Mostly cloudy with some sunny breaks in the afternoon, light west wind, freezing level rising to around 1000 m.WEDNESDAY: Sunny, moderate southwest wind, freezing level rising to around 1300 m.THURSDAY: Increasing cloud and light flurries starting in the afternoon, moderate southwest wind, freezing level rising to around 1300 m.

Avalanche Summary

On Sunday, a skier triggered a large avalanche on a north treeline slope in the Rossland area that failed on a surface hoar layer 80 cm below the surface. Skiers in the Rossland area also experience whumpfing and ski cut a size 1 wind slab on a east aspect at 1700 m. Elsewhere in the region, a natural wind slab was observed on a northwest aspect at 2150 m and explosive control produced numerous size 2 storm slabs on south aspects.On Saturday, explosive control produced several size 1-2 storm slabs in the top 15-30 cm of snow.

Snowpack Summary

Isolated flurries have delivered sporadic and localized accumulations of new snow. Snowfall amounts from the past week are 40-60 cm with the exception of the Rossland area which received 80-100 cm.A mix of interfaces 50-100 cm below the surface will potentially remain reactive to human triggering and have given sudden results in recent snowpack tests. This includes small surface hoar on polar aspects and a sun crust on solar aspects.Two deeper weak layers that formed in January and December are gradually gaining strength. Several surface hoar and facet layers are buried 1 to 2 m below the surface and there is a crust/ facet interface near the base of the snowpack. No avalanches have been reported on these layers for a few weeks and they are thought to have gone dormant at this time.

Regions covered