Avalanche Forecast

Issued: Jan 9th, 2019 4:58PM

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

Avalanche Canada kdevine, Avalanche Canada

The stormy weather continues, along with heightened avalanche hazard. Expect to find widespread reactive storm slabs, especially at upper elevations and in wind loaded areas.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Plenty of new snow, wind and warm temperatures are on the way. Forecast freezing levels are very uncertain.WEDNESDAY NIGHT - Snow, 10 cm / southeast winds, 20-50 km/h / alpine low temperature near -6THURSDAY - Periods of snow, 10-20 cm / south winds, 40-60 km/h / alpine high temperature near 0 / freezing level 1000mFRIDAY - Periods of snow mixed with rain, 20-30 cm/mm  / south winds, 60-100 km/h / alpine high temperature near +1 / freezing level 1500 mSATURDAY - Periods of snow mixed with rain, 5 cm/mm / south winds, 20-40 km/h / alpine high temperature near +1 / freezing level 1500 m

Avalanche Summary

A size 1 human triggered storm slab avalanche was reported on a south to southeast aspect at 1500-1600 m on Tuesday.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 65-80 cm of new snow (with another 10-20 by Thursday afternoon) sits on a melt-freeze crust at treeline and below. New snow and strong winds will be promoting ongoing slab formation. In some sheltered areas, the new snow is sitting on a weak layer of surface hoar (feathery crystals).For most of the region, a weak layer of facets (sugary snow) buried in early December exists down 160-220 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 approximately 70 to 150 cm.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow and wind means that storm slabs will likely be reactive to human triggering, especially in wind loaded areas.
If triggered, the storm slabs may step down to deeper layers resulting in large avalanches.Minimize overhead exposure during periods of heavy loading from new snow, wind.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Jan 10th, 2019 2:00PM

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