Avalanche forecast

Sea To Sky

Apr 13 – 14, 2018Avalanche Canada
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Avalanche danger

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

Snow and wind overnight Friday will elevate the avalanche danger.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1.5–3
    A weak layer buried 70 to 100 cm is still surprising people and producing large and destructive avalanches. Be particularly cautious around upper treeline and alpine terrain on shady aspects, where this layer is most likely to be a problem.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5
    Storm slabs are building at upper elevations. Slabs will be thicker in lee features, as the snow will fall with strong to extreme southwest winds. Rain at lower elevations will weaken surface snow and increase the likelihood of loose wet avalanches.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

SATURDAY: Snow overnight Friday, accumulation 10-15cm then cloudy with flurries Saturday / Light to moderate southwest wind / Alpine temperature -3 / Freezing level 1500m SUNDAY: Cloudy with flurries, accumulation 5-10cm / Moderate north wind / Alpine temperature -2 / Freezing level 1300m MONDAY: Cloudy with isolated flurries / Light southwest wind / Alpine temperature -1 / Freezing level 1400m

Avalanche Summary

On Wednesday and Thursday there were numerous explosives triggered storm slab avalanches to size 1 and 1.5. Additionally there were explosives triggered cornice falls to size 2.

Snowpack Summary

20-25cm of new snow Friday has been redistributed by strong to extreme southwest winds. Reactive storm slabs and wind slabs built with continued snow and wind over the past 2 days. Ridgelines are heavily corniced and if they fail they would act as a trigger on the slope below. A weak layer consisting of surface hoar, facets, and/or a melt-freeze crust from late March is now buried about 60 to 120 cm down. This layer is spotty in its distribution but has recently produced large avalanches. It is mostly likely to be problematic on west, north, and east aspects between 1900 m and 2250 m. Below this, the snowpack is well-settled and strong.

Regions covered