Avalanche Forecast

Issued: Jan 8th, 2019 4:23PM

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

kdevine, Avalanche Canada

Northwest Coastal.

With up to 30 cm forecast by Wednesday afternoon with strong southeast winds, expect widespread slab formation that will likely become more reactive throughout the day as the snow piles up.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

TUESDAY NIGHT - Periods of snow, 10-15 cm / southeast winds, 20-50 km/h / alpine low temperature near -11WEDNESDAY - Periods of snow, 10-15 cm / southeast winds, 20-50 km/h / alpine high temperature near -4 THURSDAY - Periods of snow, 15-20 cm / south winds, 40-60 km/h / alpine high temperature near 0 / freezing level 1000mFRIDAY - Periods of snow and rain, 20-30 cm / southwest winds, 60-100 km/h / alpine high temperature near +2 / freezing level 1700 m

Avalanche Summary

Reported avalanche activity from Monday:A human triggered size 2-2.5 avalanche was reported in the Hidden Lake area. Information on this avalanche is somewhat limited, but it was reportedly a wind slab avalanche on a lee alpine feature. A report of this incident can be found on the Mountain Information Network. Click here to read the report.A size 1.5 human triggered avalanche was reported in the Terrace area on a southeast to east aspect at 1200-1400 m One natural size 1.5 avalanche was reported on a wind loaded feature.

Snowpack Summary

Up to 65 cm of new snow (and an additional 15 cm by Wednesday afternoon) sits on a melt-freeze crust at treeline and below. New snow and strong winds will be promoting ongoing slab formation. The new snow may be sitting on a weak layer of surface hoar (feathery crystals) in sheltered areas.For most of the region, a weak layer of facets (sugary snow) buried in early December exists down 150-200 cm. It is likely that this layer was the culprit of a large, remotely-triggered avalanche on December 30 near Terrace, described in a MIN report here. The likelihood of triggering this layer is decreasing, but it could be triggered by humans in shallow snowpack areas. The potential may also exist for storm slab avalanches to step down to this layer, resulting in large avalanches.In the northern part of the region, near Ningunsaw pass, a couple of weak layers of surface hoar may be found that were buried near the end of December. Expect to find these layers about down approximatelyÂ 50 to 120 cm.

Problems

Storm Slabs

Storm slabs will likely be most reactive in wind loaded areas, and where the new snow sits on a melt-freeze crust.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Minimize overhead exposure during periods of heavy loading from new snow, wind.If triggered, the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 9th, 2019 2:00PM