Avalanche Forecast

Issued: Dec 14th, 2022 4:00PM

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

Avalanche Canada CB, Avalanche Canada

Use extra caution in previously unskied terrain, especially around treeline.

Have a look at a blog from the Avalanche Canada forecasters on how to manage a persistent slab problem in the backcountry.

Summary

Confidence

Moderate

Avalanche Summary

The past few days we have observed isolated natural, solar induced, point releases sz 1.5, along the highway corridor.

A skier triggered a sz 1.5 near the Dome col on Monday.

More reports came in about unsupported pockets of soft slab failing on Dec 5 and Nov 17, mainly occurring around treeline and morainal features. Most avalanches were small (sz 1 or less), but still large enough to bury a person in a terrain trap.

Scary persistent slab incident in the RMR backcountry from Monday; see MIN report.

Snowpack Summary

Surface conditions include sun crust on steep, solar aspects TL and Alp, and growing surface hoar. In general the snowpack is faceting with continued cool conditions, this combined with a below average snowpack is making for a unusually weak Selkirk snowpack with lots of BTL terrain roughness(ie. alders, rocks, trees, creeks).

Settled HST over the Dec 5 persistent weak layer in down 30-40 cm. It consists of surface hoar, preserved stellars, facets, and a thin sun crust on steeper solar aspects.

The Nov 17th Surface Hoar is now buried 60-90cm and continues to produce sudden results in snowpack tests.

Weather Summary

Dry, cool weather continues as a high pressure ridge effects the region. Flurries are possible, but no significant accumulations until Saturday. Ridge top winds are forecast to be Mod to strong from the North through Friday. Alpine temp high's are forecast to be around -9*C.

Terrain and Travel Advice

  • Uncertainty is best managed through conservative terrain choices at this time.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Exercise caution on steep, unsupported slopes.

Problems

Persistent Slabs

An icon showing Persistent Slabs

The Nov 17 and Dec 5 surface hoar are down ~75cm and ~35cm respectively, and most reactive around tree line. These layers give 'sudden' results in snowpack tests. If triggered, these layers can produce avalanches across continuous and broken features.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 15th, 2022 4:00PM

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