Avalanche forecast

Kootenay Boundary

Apr 11 – 12, 2016Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
No rating
Treeline
No rating
Below
No rating
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Highlights

Spring Conditions. Forecast cloud cover, cooler air temperatures, and dropping freezing levels will all contribute to decrease the likelihood and size of avalanches. Avoid slopes that do not develop a solid crust overnight.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    The likelihood of natural cornice falls will drop as the cloud cover increases and the freezing levels drop.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Loose wet avalanche activity is expected to decrease with forecast cloud cover and descending freezing levels. Watch for slopes that do not re-freeze overnight.

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–5
    Wet slab avalanche activity is expected to decrease with forecast cloud cover and descending freezing levels. Watch for slopes that do not re-freeze overnight.

Weather Forecast

High cloud developing overnight with freezing levels dipping down to 2000 metres by morning. Mix of sun and cloud on Tuesday morning, becoming cloudy with moderate southwest winds in the afternoon. Freezing levels dropping to 1500 metres by Wednesday morning with moderate to strong southwest winds and 3-5 cm of new snow above 1500 metres. Cloudy with moderate winds during the day on Wednesday. Mix of sun and cloud on Thursday with overnight freezing down to 1300 metres.

Avalanche Summary

No new avalanches reported.

Snowpack Summary

Cornices are large, fragile, and could trigger deep slab avalanches that run to valley bottoms. Monitoring the overnight freeze of the snow surface is very important during the spring. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating and solar radiation will weaken the snowpack much more quickly than it would if there is a well frozen thick crust. This is because the crust must first melt before the sun can weaken the snowpack. Low elevation and thin snowpack areas have become isothermal, meaning the snowpack is 0 degrees Celsius throughout. An isothermal snowpack is more prone to full depth wet slab avalanches during the heat of the day.

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