Avalanche forecast

Northwest Coastal

Feb 12 – 13, 2013Avalanche Canada
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Archived · expired 14 years ago

Avalanche danger

Thu
Fri
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

The recent storm was more intense than anticipated. Touchy, dangerous conditions will linger. Be cautious if you are venturing into the backcountry at this time.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–6
    Various crust layers in the upper snowpack (location specific) still show 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.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–6
    Rapid loading from new snow and winds has created very touchy slab avalanche conditions, especially in exposed areas.

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Synopsis: A short-lived ridge builds for Wednesday before a series of generally light precipitation bands move through Thursday and Friday.Wednesday: Mostly dry. Northwest winds around 40 km/h at ridgetop. Freezing level around 400m.Thursday: Light snowfall, 2-5cm. Southwest winds to 50 km/h at ridgetop. Freezing level 800m in the afternoon.Friday: Light or locally moderate snowfall, 5-10cm. Perhaps a little more towards the coast. Extreme southwest winds, gusting up to 90km/h at ridgetop.

Avalanche Summary

A widespread avalanche cycle up to size 3 was reported in response to the recent intense storm. The most activity appears to have been close to Terrace.

Snowpack Summary

A big dump of snow brought up to 80cm and an average of about 40cm new to the region on Tuesday. Strong winds have blown the new snow into wind slabs in exposed lee areas. The new 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 buried crusts exist within the snowpack, 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, except with very big loads, such as a cornice fall. The mid and lower snowpack layers are generally well settled..

Regions covered