Avalanche Forecast

Issued: Dec 13th, 2018 4:52PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Storm Slabs.

Avalanche Canada kdevine, Avalanche Canada

A Special Public Avalanche Warning (SPAW) is in effect for this region. Warming temperatures and strong winds are expected to give way to a natural avalanche cycle. Seek out low angle terrain free of overhead hazard.

Summary

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

THURSDAY NIGHT - Flurries, 5-15 cm / south to southwest winds, 30-55 km/h / freezing level 1100m / alpine low temperature near -5FRIDAY - Mainly cloudy with flurries , up to 10 cm / south to southeast winds, 40-80 km/h / freezing level 1400-1700m / alpine high temperature near -2SATURDAY - A mix of sun and cloud with isolated flurries / south to southwest winds, 20-45 km/h / freezing level 900m / alpine high temperature near -8, low temperature near -12SUNDAY - Cloudy with sunny periods and isolated flurries / south to southeast winds, 20-45 km/h / freezing level 1200m / alpine high temperature near -2, low temperature near -9

Avalanche Summary

Numerous avalanches up to size 3 were reported in the North Columbia region on Wednesday. The storm slab has been very reactive, producing both natural and human triggered avalanches. Several of these avalanches were triggered from a distance (remote triggered).

Snowpack Summary

70-110 cm of recent storm snow sits on a weak layer that consists of facets (sugary snow), surface hoar (feathery crystals) and a sun crust on south aspects. The storm came in with moderate to strong winds that continue to persists throughout the region, creating widespread slab formation. A weak layer from mid November is now buried up to 150 cm and consists of surface hoar in shady locations, and a sun crust on steep south facing slopes. While not recently reactive, the potential may exist for storm slab avalanches to step down and trigger this deeper layer, resulting in large avalanches. The most likely place for this layer to be a problem is on steep, south facing slopes at treeline where the surface hoar sits on the sun crust.At the base of the snowpack is a crust that formed in late October. Concern for this layer is dwindling but it may still be worth considering in places such as steep, rocky, alpine terrain, especially where the snowpack is shallow. It would likely take a large trigger such as a cornice fall to produce an avalanche on this layer.

Problems

Storm Slabs

An icon showing Storm Slabs
Significant recent snowfall, strong winds and rising freezing levels will mean widespread, reactive storm slabs will persist today.
Storm slabs in motion may step down to deeper layers and result in very large avalanches.Use conservative route selection, choose low angle and supported terrain.Avoid avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1.5 - 2.5

Valid until: Dec 14th, 2018 2:00PM

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