Avalanche Forecast

Issued: Dec 17th, 2022 4:00PM

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

Avalanche Canada trettie, Avalanche Canada

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Be aware that if triggered, avalanches may step down to deeper layers resulting in large, destructive avalanches. Keep your terrain choices conservative and be prepared to back off quickly if you find signs of instability like whumpfing and shooting cracks.

Summary

Confidence

Moderate

Avalanche Summary

Avalanche activity in the region has tapered off during the week. Over the last weekend the mid November surface hoar layer was very reactive throughout the region as well as the rest of the Selkirks and Monashees. This layer will likely remain rider triggerable in specific sheltered terrain features.

Snowpack Summary

Recent clear periods have formed large surface hoar on sheltered slopes and a sun crust on south facing terrain.

A small layer of surface hoar from early December can be found down 30 to 50cm in sheltered and shaded terrain. On south facing slopes this layer is a thin crust.

A weak layer of large surface hoar crystals, facets and a melt-freeze crust from mid November sits 50-80 cm deep. This layer has been reactive at treeline between 1700-2200 m, on all aspects producing large remotely triggered avalanches.

Below the mid-November layer is a generally weak, faceted snowpack. Snowpack depths average 80-160 cm in the alpine.

Weather Summary

Saturday Night

Scattered flurries bringing up to 5cm of new snow. Light to moderate westerly wind. Low of -14 at 1500m.

Sunday

Scattered flurries bringing up to 5cm of new snow. Light to moderate southwest wind. High of -11 at 1500m.

Monday

A mix of sun and cloud with light flurries bringing trace amounts of new snow. Light to moderate west winds and temps falling throughout the day to -18 at 1500m.

Tuesday

A mix of sun and cloud with light flurries bringing trace amounts of new snow. Light to moderate southwest winds and a high of -15 at 1500m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • Don't let the desire for deep powder pull you into high consequence terrain.

Problems

Persistent Slabs

An icon showing Persistent Slabs

There are now two persistent weak layers within the snowpack.

A 30 - 40 cm soft slab sits above a weak layer of surface hoar on shaded aspects and crust on steep solar aspects.

A second weak layer of surface hoar and facets from mid-November is buried down 50 to 80cm in the region.

While avalanche activity has tapered off on these layers they likely remain rider triggerable in specific sheltered terrain features at treeline and below.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Wind Slabs

An icon showing Wind Slabs

Northwest winds have likely redistributed snow. forming wind slab on southerly and easterly aspects and cross loaded others. New wind slabs could be more reactive where they overlie crusts, facets or surface hoar.

Aging wind slabs formed by previous southwest wind may remain reactive to human triggers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 18th, 2022 4:00PM