Avalanche forecast

Northwest Coastal

Apr 7 – 8, 2015Avalanche Canada
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Avalanche danger

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

Sunshine are warmth are the primary drivers of avalanche hazard. Avoid large sun drenched slopes if the snow is getting moist or wet.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    The March 25th persistent weak layer is still on the radar and should be treated with respect. It could be triggered by a smaller wind slab or a loose wet avalanche, or by a rider in the wrong spot.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Sunny skies and daytime warming could lead to loose wet surface sluffs on steep sunny slopes. Also, give cornices a wide berth.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Wednesday: Mainly sunny. The freezing level peaks near 1500 m. Ridge winds are light to moderate from the S-SW. Thursday: Increasing cloud with snow developing late. The freezing level is around 1300-1400 m. Winds increase to strong or extreme from the S-SW. Friday: Moderate snow. The freezing level is near 1000-1200 m and winds are strong from the south.

Avalanche Summary

On Monday there was a report of a size 2 skier triggered slab and a size 1.5 remotely triggered slab in the northern part of region. These were both from alpine terrain and appeared to fail on a buried surface hoar layer. In the same part of the region a size 3.5 cornice triggered slab was reported from steep unskiable terrain. This likely released on a weakness near the base of the snowpack. Besides these two slabs, the only other reports are of small loose wet sluffs from steep sunny slopes.

Snowpack Summary

Recent storm snow accumulations vary across the region, with the greatest amounts near the coast. The storm snow sits on a variety of old snow surfaces including a layer of surface hoar and facets buried on March 25th. This weakness, now down approximately 40 to 60cm has the potential for propagating over large areas. The problem seems more touchy in the northern part of the region, but has been reported throughout the northwest coastal area. The early March facet/crust persistent weakness is now down over a metre and produces hard, sudden planar results in snowpack tests.

Regions covered