Avalanche forecast

Northwest Coastal

Mar 5 – 6, 2014Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Stormy weather is on the horizon! Weather models aren't in total agreement on how much snow will fall on Friday, but somewhere in the ballpark of 20-40 cm is a good guess. Either way, avalanche danger is on the rise.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Strong easterly outflow winds continue to scour windward slopes and create hard wind slabs in areas that still have snow available for transport.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    Triggering the mid February persistent weakness is unlikely until the weather changes (Friday!). Caution is still recommended on higher north aspects. 

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Thursday: Mainly cloudy with a chance of flurries – around 5 cm. The freezing level is at the surface. Ridge winds are light to moderate from the S-SW. Friday: Moderate to heavy snowfall – 20-40 cm (heaviest along the coast). The freezing level climbs to 1200 m in the south and 500 m in the north. Winds are strong from the SW. Saturday: Moderate precipitation. The freezing level is between 1000 and 1500 m. Winds are moderate to strong from the SW.

Avalanche Summary

A few natural slab avalanches up to size 2.5 from solar aspects were reported in the northern part of the region on Tuesday. There's finally a weather change on the horizon! Expect conditions to start changing quickly on Friday and through the weekend.

Snowpack Summary

Persistent strong outflow winds (from the northeast-southeast) have scoured windward slopes and created hard or dense wind slabs in exposed lee and cross-loaded terrain. Cold clear weather has also promoted surface hoar growth and surface faceting on shady slopes and a sun crust on steep solar aspects. The mid February weak layer of surface hoar or a crust/facet combo is buried 30-90 cm deep. There has been no reported activity on this layer recently, but watch for it to wake up when the weather pattern shifts to moist and mild heading into the weekend. Basal facets and/or depth hoar remain a concern in shallow snowpack areas in the northern part of the region.

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