Avalanche Forecast

Issued: Feb 3rd, 2017 4:20PM

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

Avalanche Canada cgarritty, Avalanche Canada

Avalanche danger will increase as new snow piles up. Watch for signs of instability and take extra caution if Saturday's accumulations exceed 20 cm.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

Friday night: Scattered flurries bringing approximately 5cm of new snow.Saturday: Flurries bringing approximately 10cm of new snow in the south of the region. Only trace amounts in the north. Winds light to moderate from the east. Alpine temperatures around -14.Sunday: Cloudy with scattered flurries bringing another 5cm of new snow across the region. Winds light to moderate from the northeast. Alpine temperatures around -12.Monday: Mainly cloudy with isolated flurries and a trace of new snow. Winds light from the northeast. Alpine temperatures around -14.

Avalanche Summary

Reports from Thursday include a number of large natural cornice falls from north-facing alpine ridgetops. Although these failed to trigger slabs below, wind slabs were observed on Thursday releasing under skier traffic to Size 1. One notable report details a remote-triggered Size 1 persistent slab observed in the north of the region. Although it failed on a steep southerly slope and had a relatively shallow depth (20 cm), it was reported to have failed on our January 15 surface hoar and reinforces ongoing concerns for persistent slab problems in that part of the region. As for Saturday's outlook, fresh storm slabs are expected to be sensitive to light triggers, especially where they overlie weak layers present at our previous surface. In the north of the region around Blue River and Valemount, a persistent slab problem still exists and the potential for storm slab avalanches to 'step down' should be considered. Several large human triggered avalanches were reported last week. Click here for more details.

Snowpack Summary

New snow from Friday has now buried a range of surfaces that have developed over the past week. Along with wind slabs that recently formed on a wide range of aspects, the new snow will also bury a sun crust that was reported on steep solar aspects as well as surface hoar found on sheltered open slopes. Surface faceting was also recently reported as a result of cold temperatures over the week. A persistent weakness buried mid January is now down 30-50 cm and consists of buried surface hoar in sheltered areas, and/or widespread faceted old snow. It has generally stabilized but may be sensitive to triggering in isolated areas where buried surface hoar is preserved.Another surface hoar/facet persistent weakness was buried mid-December and can now be found down 100-120 cm. It has become inactive in the south of the region, but may still be sensitive to triggers in the northern part of the region near Blue River and Valemount. Read the Cariboo forecast for more information.

Problems

Storm Slabs

An icon showing Storm Slabs
Fresh storm slabs are forming over a weak layer of snow that was formed during recent clear weather. Expect the new snow to be especially touchy in wind-exposed areas.
Minimize exposure during periods of heavy loading from new snow, wind.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Watch for signs of instability such as whumpfing, or cracking.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 4th, 2017 2:00PM

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