Avalanche forecast

Kootenay Boundary

Feb 26 – 27, 2016Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Solar radiation is the primary factor driving the hazard this weekend.  Expect conditions to change rapidly if the sun comes out.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–3
    Solar radiation greatly increases the reactivity of wind slabs.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–4
    Avoid cornice threatened slopes if sun comes out.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–4
    This is still a layer to keep in mind, as an avalanche on this layer could be large and destructive.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

No significant snow in the forecast. Up to 5cm Friday night and another 5-10cm Sunday. Light to moderate ridgetop winds out of the southwest throughout weekend.  Freezing levels spike Friday then cool off to around 1800m for the remainder of the period. For more detailed weather information see https://avalanche.ca/weather

Avalanche Summary

On Thursday two size 1 skier triggered slab avalanches were reported on northerly aspects that failed on a surface hoar layer down 20-25cm.  The elevations of these avalanches were not reported.

Snowpack Summary

Cornices are large and looming. Old wind slabs are well bonded but could fail with daytime heating on solar aspects. The mid February layer is down 30-50cm and is a crust in most areas. This layer is generally well bonded to the overlying persistent slab. However, in isolated areas on northerly aspects at treeline elevations the February 10th surface hoar down 70-100cm is still producing moderate sudden planar shears in compression tests, though it has not been reactive to human triggers. This suggests a classic low probability, high consequence scenario.

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