Avalanche Forecast

Issued: Dec 5th, 2022 4:00PM

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

Avalanche Canada jleblanc, Avalanche Canada

Small pockets of wind slabs can still be triggered on alpine features.

Evaluate slopes on an individual basis before committing to them.

 

Summary

Confidence

Moderate

Avalanche Summary

A human-triggered slab occurred at Fissile Peak on a northwest lee slope and ran on a crust layer. Several small (size 1) wind slab avalanches were reported in the last 48 hours. Debris from loose wet avalanches (size 1) was observed on steep alpine south-facing slopes around the Whistler area.

Please keep sharing your observations via the MIN; it helps strengthen our information gathering!

Snowpack Summary

On steep south-facing slopes, a sun crust has developed over the past weekend. On shaded terrain at all elevations, large surface hoar (up to 10 mm) is present, along with unconsolidated snow. The upper snowpack consists of 20-50 cm of light snow, overlying old surfaces such as wind-affected surfaces.

Down 40-60 cm in the snowpack, a thick melt-freeze crust is found up to 2200 meters. Faceting has been observed between the wind slab and the crust. Professionals are concerned about the possibility of wind slabs fracturing at this deeper interface.

The snowpack sits around 70 to 120 cm at the treeline and up to 180 cm in the alpine. Much of the below treeline elevation band is below the threshold for avalanches.

Weather Summary

An arctic ridge of high pressure will continue to be the main attraction. Conditions will be dry until the next pulse of snow, expected Wednesday night through Thursday.

Monday Night

Cloudy. No precipitation. Light westerly ridge wind. Low -10 C. Freezing level at valley bottom.

Tuesday

Cloudy. Isolated flurries. 2 cm. Westerly ridge wind gusting 40 km/h. Low -8 C. Freezing level at valley bottom.

Wednesday

Partially cloudy. 5 cm in the afternoon. Southwesterly ridge wind up to 50 km/h. High -5 C. Freezing level around 700 m.

Thursday

Snow 15-20 cm. Southwesterly ridge wind up to 60 km/h. High of -3C at treeline. Freezing level around 800 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
  • Carefully evaluate steep lines for wind slabs.
  • The best and safest riding will be on slopes that have soft snow without any slab properties.

Problems

Wind Slabs

An icon showing Wind Slabs

Newer wind slabs have formed in cross-loaded terrain due to reverse loading. Lingering pockets of old wind slabs exist in lee features. Keep approaching convex and unsupported features with caution.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 6th, 2022 4:00PM