Avalanche forecast

Northwest Coastal

Feb 14 – 15, 2013Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Weather models are disagreeing with expected snowfall totals for Friday. Danger ratings are based on the highest forecast snowfall amounts.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–5
    Forecast rapid loading will create widespread slab avalanche conditions, especially in areas exposed to wind. Expect touchy wind slab/ storm slab conditions to prevail with the potential for large avalanches.

Confidence

Fair - Forecast snowfall amounts are uncertain on Friday

Weather Forecast

Friday: Moderate to heavy snowfall continuing overnight / Strong to extreme southwest winds / Freezing level at 800mSaturday: Light snowfall / Moderate to strong northwest winds / Freezing level at 300mSunday: Light snowfall / Light southwest winds / Freezing level at 100m

Avalanche Summary

A widespread natural avalanche cycle up to size 3 was reported in response to Tuesday's storm with the most activity appearing to occur close to Terrace. Explosives control in the region triggered lingering storm snow instabilities at treeline and above to size 2.5 on Wednesday.  Avalanche activity is expected to ramp-up again with weather forecast for Thursday evening/Friday..

Snowpack Summary

On Tuesday the region saw up to 80cm of new snow and an average of about 40cm. Strong winds have blown the new snow into wind slabs in exposed lee areas. The recent snow sits on above previous wind slabs on shady slopes in the alpine and at treeline, and a rain/sun crust at lower elevations/solar aspects, respectively.Deeper within the snowpack buried crusts exist, but are reported to have bonded well. I imagine that after the most recent avalanche cycle these will be difficult or near impossible to trigger in most areas, except with very large triggers such as a cornice fall.The mid and lower snowpack layers are generally well settled.

Regions covered