Avalanche forecast

Sea To Sky

Feb 18, 2018Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Fresh storm slabs will be reactive, especially in wind-affected terrain. Use extra caution around steep unsupported terrain features.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–2.5
    Large, looming cornices have formed along ridgelines. They need to be given an extra wide berth from above and below. A large cornice collapse in the wrong location may have the ability to trigger a large avalanche on the slope below.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    25-40 cm of fresh snow from Saturday's storm has formed reactive storm slabs, especially in wind-affected terrain at higher elevations.

Confidence

Moderate -

Weather Forecast

SUNDAY: Gradual clearing and cooling as Arctic air pushes into the region, moderate to strong northeast wind and alpine high temperatures around -15 C.MONDAY: Sunny, moderate northeast wind, alpine high temperatures around -14 C.TUESDAY: Mostly sunny, light wind, alpine high temperatures around -12 C.

Avalanche Summary

Preliminary reports from Saturday indicate storm slabs were reactive to skier and explosive triggers, producing mostly small slabs (size 1) and one larger slab (size 2) in lee terrain.Several large cornices collapses were reported last week. One resulted in a fatal accident in the Callaghan area on Saturday. A snowmobiler was parked 7-10 m back from the edge of a corniced ridge when a large chuck broke off and took the rider down the slope. See here for a full report. Cornices grew larger with Saturday's storm.

Snowpack Summary

25-40 cm of fresh snow sits above variable interfaces including hard wind-affected snow in exposed terrain, a hard crust below 1900 m, and a sun crust on south-facing alpine slopes. Deeper deposits of storm snow exist in lee and cross-loaded alpine terrain. The mid-January crust is now buried beneath 150-200 cm of settled snow, but a heavy trigger such as a cornice fall could potentially wake up this layer. The lower snowpack is generally strong and well-settled.

Regions covered