Avalanche forecast

Sea To Sky

Dec 12, 2018Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

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

Touchy storm slabs will continue be a concern as more snow and strong winds are on the way.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5
    There have been limited alpine observations due to reduced visibility with new snowfall and high winds, expect storm slabs to be more reactive in wind-loaded terrain.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

TUESDAY NIGHT: Flurries, accumulation 10cm, moderate west wind with strong gusts, freezing level rising 1000m. WEDNESDAY: Snow, accumulating 15-35 cm, moderate to strong southwest wind with extreme gusts, freezing level below 1000m. THURSDAY: Snow, accumulating 20-45cm, moderate southwest wind with extreme gusts, freezing level rising to 1400m. FRIDAY: Snow, accumulation 35-45cm, strong southwest wind with extreme gusts, freezing level 1300m.

Avalanche Summary

The new storm snow is bonding poorly to the old surface, small (size 1) storm slabs are being triggered by skier traffic. Explosives have triggered larger (up to size 2) storm slab avalanches.

Snowpack Summary

Snowfall beginning Sunday has deposited around 40-60 cm in the Sea to Sky region. Strong to extreme winds have accompanied the new snow and the weather forecast is calling for significant snowfall amounts to continue to accumulate through the week. Buried under the new snow is a weak surface layer sitting over 20-30 cm of low density faceted snow. The new snow is not bonding well with the old surface layer, has slab-like properties, and is reacting to skier traffic.Prior to this storm, alpine snowpack depths varied around 150-200 cm, with an early November crust at bottom of the snowpack (down 100-120 cm). This crust appears to be breaking down at higher elevations and has been unreactive to snowpack tests. Snowpack depths disappear quickly with decreasing elevations (starting around 1800 m).

Regions covered