Avalanche forecast

Northwest Coastal

Feb 9 – 10, 2013Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Windslabs have formed in response to westerly and southwesterly winds in exposed lee areas. Katabatic outflow winds from glaciers and icefields have also been reported. Watch for wind loaded slopes in these areas.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    Various crust layers in the upper snowpack (location specific) still shows sudden results and a propensity for propagation in snowpack tests. Local investigation to test distribution and reactivity is a good idea before committing to steep slopes.

Confidence

Good

Weather Forecast

Synopsis: Several low intensity pulses of precipitation will bring light to moderate precipitation amounts through the period, focussed mostly along extreme coastal areas.Sunday: Light to moderate snowfall starting in the afternoon (5-10 cm). Southwesterly winds around 50 km/h at ridgetop. Freezing level around 900m.Monday and Tuesday: 5-10 cm new snow each day. Freezing level around 500 m. Moderate to strong southwesterly winds.

Avalanche Summary

Avalanche activity has tapered off, with only one size 2 skier-triggered avalanche on a steep north slope reported from Friday.

Snowpack Summary

Recent weather has been relatively benign, with precipitation pulses giving incremental loading (5-10cm at a time). Relatively light winds have accompanied these snowfall pulses with some stronger outflow winds closer to the coast. At elevations below 1300 m you might find a crust on the surface from warm temperatures and/or from previous drizzly rain.In the upper snowpack, various melt-freeze crusts remain a concern. Depending on your location, you may encounter crusts as shallow as 40cm and as deep as 110cm. Recent compression tests show both resistent and sudden planar results and an extended column test showed a continued propensity for propagation if the layer was triggered. It is certainly worth keeping these layers on your radar in regards to distribution and reactivity in the areas that you are riding. The mid and lower snowpack is generally well settled..

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