Avalanche forecast

Northwest Coastal

Mar 14 – 15, 2016Avalanche Canada
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Avalanche danger

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

Avoid steep, fat looking slopes and wind loaded features.  They could be reactive to human triggering through the storm on Tuesday

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    A layer of buried surface hoar or facets down 70-100cm has recently been reactive around Stewart and north. An old weak crust layer down over 1m remains a concern in the south of the region.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    New snow will settle into increasing reactive soft slabs in steep unsupported slopes and lee slopes through the day.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Tuesday

Weather Forecast

TUESDAY: Light snowfall brings up to 15cm overnight and 10 through the day, light to moderate southwesterly winds, 1000m freezing level. WEDNESDAY: Flurries with accumulations of up to 10cm. light westerly winds, 1000m freezing level. THRUSDAY: mainly sunny, light and variable winds, 1000m freezing level.

Avalanche Summary

Wind slab avalanches were triggered by explosive control on Sunday and lingering stubborn wind slabs may still be reactive to human triggering. Several natural and artificially triggered cornice collapses in the last week have caused large avalanches in the alpine. On Thursday of last week, a natural size 3.5 persistent slab avalanche was reported in Bear Pass. This avalanche occurred on a northwest aspect at 1350m elevation and released on the late-February surface hoar layer.

Snowpack Summary

New snow is falling on  widely wind effected old surfaces, burying wind pressed snow in exposed terrain and soft or hard slabs in lee features. Moist snow can be found at lower elevations and on solar aspects. A layer of surface hoar or facets down 70-100cm can be found in areas north of Stewart sitting below Marchs accumulated storm snow. Recent avalanche activity suggest that we may be approaching a critical load on this interface. An older crust/facet layer buried in early February can now be found around 80-120 cm below the surface, however, this layer has been dormant recently. Cornices are reported to be large and fragile.

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