Avalanche forecast

Northwest Coastal

Feb 22 – 23, 2016Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Watch for intense sun, moist snow on the surface or fresh natural avalanche activity as signs that avalanche danger is increasing though the day.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    Several buried weak layers remain a concern depending on where you are. Large avalanches can be triggered from thin spots or by heavy loads such as cornice releases. Smaller avalanches in motion have the potential to step down to these layers.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Lingering storm slabs may be found on steep unsupported slope and in freshly wind loaded alpine features. If the sun comes out it could trigger fresh avalanche activity.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Thursday

Weather Forecast

TUESDAY: mainly sunny, light to moderate southerly winds, freezing level 100m. WEDNESDAY: partly cloudy with flurries possible in the afternoon, light to moderate southerly winds, freezing level rising to 1500m. THURSDAY: snow overnight and through the day up to 10cm possible, moderate to strong S winds, freezing level 1500m.

Avalanche Summary

A couple of natural and skier triggered storm and wind slab avalanches with limited propagations were reported over the weekend. Cornices are fragile and should be avoided. Northeast of Bell 2 a natural avalanche at treeline was observed to have stepped down to the early January surfaces hoar. While this avalanche technically occurred in the Northwest Inland region it is a good reminder that this layer remains a concern, especially in the thinner snowpack areas.

Snowpack Summary

The recent storm snow continues to settle and gain strength although some lingering mid-storm instabilities are still showing up in snow profiles. A thin crust may cap moist snow at lower elevations and on slopes that see direct sun. Recent winds have formed wind pressed surfaces in exposed terrain and loaded lee features. 40-100cm of snow now sits above a melt freeze crust buried on February 12th. This crust extends up to about 2000m. Although the upper snowpack is bonding well to this crust in most places, some recent snow pit tests northwest of Terrace produced failures on this layer, or in facets just below it under moderate to hard loads. Bellow this, a layer of surface hoar buried late in January remains a concern for the thinner snowpack areas in the east and north of the region. Shallow snowpack areas also have a weak base layer of facetted snow just above the ground.

Regions covered