Avalanche Forecast

Issued: Jan 8th, 2018 4:33PM

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

Avalanche Canada pgoddard, Avalanche Canada

Lots of uncertainty in the snowfall forecast for Tuesday and Wednesday. Danger ratings reflect forecast intense snowfall.

Summary

Confidence

Low - Forecast snowfall amounts are uncertain

Weather Forecast

TUESDAY: Cloudy with snow. One senior meteorologist is predicting a 'Fernie effect', which could bring up to 50 cm of dry snow in quick order late in the day. Light to moderate winds. Alpine temperature near -6.WEDNESDAY: Light winds. Light snow. Alpine temperature near -10.THURSDAY: Light winds. Moderate snow. Alpine temperature near -10.

Avalanche Summary

Explosives triggered several size 1.5-2.5 storm slabs on Monday morning. Skiers were also triggering loose dry avalanches which were gathering mass and running up to size 2. Reports of persistent slabs being triggered by people, machines and even remotely (from a distance) continue to come in, particularly at and below treeline. Check out the reports on the Mountain Information Network here. On Thursday, a skier-triggered size 2 slab on a north-east aspect at 1975 m near Fernie caught and partially buried four people. Check out the details here. Touchy avalanche conditions will continue as new snow continues to stress weaknesses in the snowpack.

Snowpack Summary

New snow is building storm slabs. Old and new wind slabs and cornices can be found at ridge top. If intense snowfall rates occur, loose snow avalanches are likely to run fast and far. A very touchy weak layer from mid-December (predominantly feathery surface hoar crystals and/or a sun crust) is found down about 40-90 cm. It is most prevalent at and below treeline, and seems particularly volatile between about 1600-1800 m. Deeper in the snowpack, an early season rain crust and sugary facets make up the picture. It is possible that a shallower avalanche could step down to these layers, creating a surprisingly large event.

Problems

Storm Slabs

An icon showing Storm Slabs
Incoming snow is likely to create touchy new storm slabs and loose snow avalanches.
If triggered, storm slabs may step down to deeper layers resulting in large avalanches.Watch your sluff: it may run faster and further than you expect.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
New snow may overload already touchy weak layers, making for volatile avalanche conditions.
Back off if you encounter whumpfing, hollow sounds or shooting cracks.Stay off convex or unsupported slopes at and below treeline.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 9th, 2018 2:00PM

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