Avalanche forecast

Northwest Coastal

Apr 9 – 10, 2016Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
No rating
Treeline
No rating
Below
No rating
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Highlights

Spring conditions typically means hazards are greatest during the heat of the afternoon. Start early, finish early.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    Large cornices weaken with warming and sun. The timing of failures is unpredictable. Dropping chunks are a hazard in themselves and they may also trigger a slab avalanche on the slopes below. Watch and limit your exposure to overhead hazards.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Loose wet sluffing is likely on sun exposed slopes with sunshine or warm afternoon temperatures. Increased warmth may increase the size and length; wet slabs are also possible.

Weather Forecast

Sunday is expected to be another sunny day (lots of solar radiation) with afternoon temperatures even warmer than Saturday. Light wind. No new precipitation. Monday and Tuesday look cloudy and cooler as a weak disturbance approaches the coast. Only trace amounts of precipitation are expected Monday with 5 to 10 mm of rain or snow on Tuesday. Freezing level both days around 1500 m.

Avalanche Summary

With the arrival of spring, field observations and data are very limited in the region. No new avalanche reports does not mean avalanches are not occurring. One should expect cornices to continue to fail, at times triggering avalanches on the slopes below. Similarly, one must expect solar radiation and warm temperatures to weaken the snowpack, triggering loose wet and wet slab avalanches.

Snowpack Summary

Moist or wet snow exists on all aspects at all elevations. Any surface crusts that form overnight will quickly break down during the day. The snowpack's strength is directly related to the thickness and strength of these crusts. Where there are layers in the snowpack, they are generally bonding. A widespread crust/facet layer from early February and depth hoar at the bottom of the snowpack (primarily in northerly & inland areas) are dormant. Strong, thick crusts in the upper parts of the snowpack have limited the reactivity of these old layers; however, they could potentially once again produce isolated yet large avalanches with prolonged periods of warming.

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