Avalanche forecast

Sea To Sky

Mar 30 – 31, 2017Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

The weather forecast calls for a short period of more settled weather

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3
    With recent warm temperatures, snow and wind cornices have grown large and overhanging. While cornices are a hazard in themselves, the danger increases when they have the potential to act as a trigger to slabs sitting beneath them.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–3
    New storm slabs are expected to continue to be reactive as the sun comes out on Thursday. The new snow could present as loose wet avalanches at lower elevations or on steep sun exposed slopes at upper elevations.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Friday

Weather Forecast

FRIDAY: Mix of sun and cloud / Light southwest wind / Alpine temperature -2 / Freezing level 1300mSATURDAY: Flurries, accumulation 5cm / Moderate southwest wind / Alpine temperature -2 / Freezing level 1300mSUNDAY: Mix of sun and cloud / Light to moderate west wind / Alpine temperature -1 / Freezing level 1200m

Avalanche Summary

A report from Tuesday indicated a natural size 2 cornice failure that was suspected to be triggered by warming temperatures at tree line on a west aspect. Additionally, on Tuesday and Wednesday several explosive and skier controlled avalanches to size 2 and 2.5 were reported from a variety of aspects. These were mostly wind and storm slabs failing 10-40cm deep. Some were also triggered by cornices pulling out 20-40cm slabs on slopes below.

Snowpack Summary

A series of snowfalls over the early part of the week accumulated 30-60cm of storm snow that has been redistributed by predominantly southwest and southeast winds. 2000m and below, the storm snow lies above a crust that formed last week. A rain crust that was buried mid March is now 90-120 cm deep. The mid-February crust/facet layer can still be found at the upper end of tree line and into the alpine. This layer is generally 120-170 cm deep but may be present nearer to the surface in wind scoured areas. Although there is growing confidence that this layer seems to be becoming dormant, a storm slab or cornice release in the right location may have the potential to trigger any of the deeply buried weak layers.

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