Avalanche forecast

Northwest Coastal

Dec 18 – 19, 2015Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Incremental loading of new snow and wind over variable buried weak layers will trend the avalanche danger up. Watch for clues like whumphing settlements and evidence of natural activity on steep wind exposed terrain.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–4
    Areas with buried surface hoar down around 100 cm may continue to be triggered by light loads in weak spots around exposed rocks or trees. This layer of buried surface hoar is variable across the region.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    New storm slabs have developed in the alpine and at treeline. Pockets of wind transported snow may be deep due to strong winds during the storm.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Sunday

Weather Forecast

Flurries and light snow overnight with moderate south west winds and freezing levels at valley bottoms. Snow beginning Saturday morning with increasing southwest winds, expect 10-15 cm during the day. Another 10-15 cm is expected by Sunday morning, with more possible in the south near Kitimat as the storm center looks to pass just to the south of the region. Incremental loading should continue on Sunday with another 5-10 cm and 10-15 by Monday morning.

Avalanche Summary

No new avalanches reported. Extensive wind effect reported in the alpine and at treeline.

Snowpack Summary

New snow continues to slowly build the load above buried weak layers. There is 15-25 cm above the December 17th (151217 SH) surface hoar, and 25-40 cm above the December 14th (151214 SH). At this time, the new snow continues to come in cold and dry and may not have the load needed to settle into a cohesive slab above these weak layers. The early December layer buried on the 1st or 2nd (151201 SH) is now down a metre or so depending on your area. This layers distribution is variable. In some areas, this layer may be sensitive to human triggering and wide propagations while in other areas it is non-existent or has gained significant strength.  Most of this information is coming from the Shames area or from commercial operations near Terrace. Conditions may be different close to Kitimat, where it looks like recent snowfall amounts may be a bit higher and temperatures a bit warmer. The north of the region has a shallow early season snowpack and may have weak facetted crystals near the ground due to cold temperatures over a thin snowpack.

Regions covered