Avalanche forecast

Northwest Inland

Apr 16 – 17, 2012Avalanche Canada
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Avalanche danger

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

Daily bulletins with danger ratings are finished for the season for this region. General advice can be found in the Avalanche Problems section and on the Forecast Details tab below. Additional information can be found in the Forecaster Blog.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–6
    Large cornices exist in alpine terrain. A failure could be destructive by itself, and could also trigger an avalanche on the slope below.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–5
    Snow stability can deteriorate very quickly with warm spring temperatures. Watch for loose wet avalanches on steep terrain, especially under direct solar radiation.

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–5
    Snow stability can deteriorate very quickly with spring temperatures. Melt freeze crusts are common in the spring and provide ideal sliding surfaces for wet slabs. Destructive glide cracks also fall into the wet slab category.

Weather Forecast

Avalanche Summary

Spring conditions exist in the region. Avalanches are most likely to occur in response to solar radiation, warm temperatures, and periods of rain. Particularly dangerous conditions may develop during prolonged periods of warming, heavy rain, or on days with no overnight freeze. Under these conditions, surface avalanches may step down and trigger deeper wet slab avalanches. Prolonged warming may also weaken large and destructive cornices, which are a danger in themselves or could act as a heavy trigger on the slope below. Typically, avalanche activity ramps up during the day and is at a peak during the afternoon. If it's raining or there was no overnight freeze, avalanche activity can happen at any time.

Snowpack Summary

As we transition into spring the surface layers have a great deal of influence on the snowpack. When there is a solid re-frozen surface crust, travel is fast and easy, and the snowpack is held together by the surface cap. Any deeper persistent weak layers are unlikely to fail until the surface cap breaks down from daytime heating. During warm conditions, melt water is able to percolate within the snowpack and cause deeper weak layers to fail. If it cools off and snows, new snow may not bond well to the hard spring crusts, and isolated storm and wind slabs can easily develop.

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