Avalanche forecast

Northwest Coastal

Jan 15 – 16, 2014Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Snowfall forecast is highly variable throughout the region, the North seeing the most accumulation. The posted danger rating apply to areas with less accumulation.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    3–6
    The facet/crust or surface hoar down 100 cm and the basal facets layers are gaining strength but could still be triggered by a heavier load such as a cornice fall or a windslab avalanche stepping down.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    North of Steward, storm slab and wind slabs on NE facing slopes will keep developing . South of Steward, windslabs will be the main concern.

Confidence

Good

Weather Forecast

Tonight and Thursday: A warm front is moving North along the coast and will bring moderate precipitation on the Northern part of the region till Thursday night and rising freezing levels on the whole region reaching 2000 m by the afternoon Thursday. Winds are expected to keep blowing strong from the SW. The South should start to see some clearing by the afternoon.Friday: The whole Coast is under a high pressure system, clearing skies, moderate to strong SW switching from the S and freezing levels reaching 2000 m. Saturday: A frontal system is expected to reach the coast and bring moderate precipitation with freezing levels around 1000-1500 m.

Avalanche Summary

There was an avalanche cycle yesterday at all elevation and on all aspects. Multiple natural releases up to size 3.5 with deep crowns and wide propagation.

Snowpack Summary

In the Northern part of the region, the moderate snow accumulation, strong winds and rising temperatures forecasted for tomorrow will most likely keep avalanche conditions active. Storm slab will keep developing as well as windslabs in the alpine and at top of treeline lee of SW winds. It is possible that avalanches in the storm snow or in a windslab could step down to the 80-100 cm surface hoar layer that was buried in early January at treeline or to the basal facets mostly in thin, rocky alpine features. In the longer term, these deep instabilities should gain strength with the mild temperatures.South of Steward, the main concern will be developping windslabs lee of SW winds in the alpine which will most likely be touchy.For the whole region, the rise in temperature will weaken the snowpack and could act as a trigger especially above 1500 m where the storm snow and windslabs will receive a heat shock. If the sun comes out, I expect steep S-SE facing slopes to see increase avalanche activity. Under this elevation, a rain crust has formed but warm temperatures could create the possibility of loose wet avalanches as the surface keeps heating up.

Regions covered