Avalanche forecast

Northwest Coastal

Apr 12 – 13, 2014Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

The timing of the this weekend's big warm-up is difficult to forecast. If Sunday ends up being the warmer day, Sunday's avalanche danger may be higher than posted.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–5
    Snow and strong winds have built deep storm slabs at higher elevations. Warmer temperatures and solar radiation will likely de-stabilize the new snow and activate a natural avalanche cycle. Cornices may also fail with warming.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–4
    Watch for loose wet avalanches with daytime warming on steep, sun-exposed slopes. Loose wet avalanches can be pushy and entrain mass quickly.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–7
    Deep persistent avalanches would be very large and highly destructive. Possible triggers include cornice fall, a surface avalanche in motion, warming and intense solar radiation.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Sunday

Weather Forecast

Sunday: Clear skies / Light and variable winds / Freezing level at about 2000mMonday: Clear with increased cloud late in the day / Light to moderate southwest winds / Freezing level at about 1500mTuesday: Overcast skies with very light precipitation / Light westerly winds / Freezing level at about 1300m

Avalanche Summary

In recent days numerous loose wet, and wet slab avalanches were reported up to size 2 from steeper start zones at treeline and below treeline. A widespread natural avalanche cycle up to size 4 occurred over the past 5 days and deep persistent weak layers became overloaded, initiating very-large avalanches. In shallower snowpack areas, storm slab avalanches have stepped down to the December facet/ depth hoar layer. Natural avalanche activity will likely continue through the weekend with sunny skies and a rapid rise in freezing levels.

Snowpack Summary

A recent storm has brought 90+ cm or more to coastal regions forming thick storm slabs on leeward features. Warmer temperatures have helped to settle the recent snow, although the storm snow may continue to be touchy where it overlies surface hoar, crusts and/or facets buried on April 2nd. At lower elevations the snowpack has been saturated by rain and may exist as wet snow or a refrozen crust. Large cornices have formed and loom over slopes below.The early February crust/facet layer is down 150 - 240 cm. This layer has become overloaded by recent storm loading and is failing in some places resulting in very-large avalanches.

Regions covered