Avalanche forecast

Northwest Coastal

Dec 19 – 20, 2015Avalanche Canada
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Avalanche danger

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

Forecast new snow and wind will continue to add to the load of storm snow. Conservative terrain selection is recommended during the stormy weekend.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–4
    No new reports of avalanches on this weak layer. Watch for continued loading above this weak layer at and near treeline. Low likelihood, but high consequence if you trigger this buried surface hoar.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    Storm slabs continue to develop with each pulse of new snow and wind. Cool temperatures may be limiting slab development.

Confidence

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

Weather Forecast

10-15 cm of new snow is forecast overnight with strong southerly winds and freezing levels around 200 metres. Another 5-10 cm is forecast during the day Sunday with moderate westerly winds. The south of the region around Kitimat may see enhanced snowfall as the low pressure moves onshore in the central coast. Continued light snow on Monday with slightly higher freezing levels near 500 metres. Tuesday mostly flurries with cooler temperatures and a chance of broken skies.

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