Avalanche forecast

Northwest Coastal

Apr 2 – 3, 2018Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Fresh storm slabs will form above a hard crust on Tuesday, plus there's a lingering possibility of large persistent slab avalanches. Conservative terrain choices are recommended.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3
    Last week, a surface hoar layer buried 50-90 cm produced large slab avalanches that propagated widely. There's some uncertainty as to how long this layer will remain a problem, but it's best to avoid sheltered north-east slopes in the meantime.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    15-25 cm of new snow with moderate southwest wind may form fresh slabs on Tuesday. Slabs will be extra thick and reactive in areas that get enhanced snowfall or extra loading from blowing snow.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

TUESDAY: Snow starting Monday afternoon will continue overnight and then ease off on Tuesday afternoon, accumulations of 15 to 25 cm, moderate southwest wind, alpine high temperatures near -8 C, freezing level up to 500 m.WEDNESDAY: Mostly cloudy with light snowfall, accumulations of 1 to 3 cm, light south wind, alpine high temperatures near -6 C, freezing level up to 700 m.THURSDAY: Snow starting in the morning with accumulations of 5-10 cm by the afternoon, light south wind, alpine high temperatures near -8 C, freezing level up to 500 m.

Avalanche Summary

Avalanche activity on Sunday was limited to a few small loose avalanches on steep sun-exposed slopes.On Saturday, a large persistent slab avalanche was reported in the north of the region, failing on the early-March weak layer. It failed on an easterly aspect around treeline. Otherwise, there was further evidence of Friday's natural cycle of storm slab and loose dry avalanches. They were small to large (size 1 to 2) and observed on all aspects and at all elevations.Last week, large persistent slab avalanches were reported on east to northeast aspects at all elevations. These were failing on the early-March and mid-March layers.

Snowpack Summary

Moderate amounts of new snow are expected in the region, but accumulations could reach 30 cm in some localized areas. The new snow will fall on a hard crust layer on south-facing slopes and at elevations below 800-1200 m.In the south of the region, there is about 70 to 90 cm of snow from last week that overlies two layers of surface hoar, which are most prominent on north to east aspects and were buried early-March and mid-March. In the north of the region, these layers are around 40 cm deep.Shallower parts of the region, such as the far north, have weak sugary facets near the bottom of the snowpack.

Regions covered