Avalanche forecast

Sea To Sky

Apr 14 – 15, 2018Avalanche Canada
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Avalanche danger

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

Slabs have been reactive to human traffic, particularly in lee terrain features. The likelihood of triggering avalanches will increase if the sun comes out, so best to avoid southerly slopes under intense sun.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2.5
    Recent snow has created new slabs, which are up to 1 m thick in lee features due to strong south winds. Precipitation fell as rain at low elevations, so expect wet snow. Loose wet avalanches are possible if the sun comes out.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–3
    A weak layer buried 60 to 140 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.

Snowpack Summary

30 to 40 cm of new snow between Thursday and Saturday has been redistributed by strong south winds, forming reactive storm and wind slabs up to 1 m deep.  Ridgelines are heavily corniced and if they fail they could trigger slabs on slopes below.A weak layer consisting of surface hoar, facets, and/or a melt-freeze crust from late March is now buried about 60 to 140 cm. 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.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

SUNDAY: A mix of sun and cloud, light northeast winds, alpine temperature -4 C, freezing level 1500 m.MONDAY: Cloudy with light snowfall, accumulation 5 to 10 cm, light west winds, alpine temperature -5 C, freezing level 1400 m.TUESDAY: Mostly cloudy, light west winds, alpine temperature -5 C, freezing level 1400 m.

Avalanche Summary

On Friday, many small to large (size 1 to 2) storm and wind slabs were explosively controlled and ski cut across the region.  They were generally at treeline and alpine terrain with slab depths of 20 to 50 cm.  Cornices were also reactive to explosives but were generally small.

Regions covered