Avalanche Forecast

Issued: Dec 28th, 2021 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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If wind speeds increase on Wednesday avalanche danger will be heightened on freshly wind loaded slopes.

Summary

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

Cold arctic air will persist until Sunday.

TUESDAY NIGHT: Clear skies, no precipitation, moderate wind from the north with gusts to 50 km/h, treeline temperatures drop to -15 C.

WEDNESDAY: Mostly sunny with some afternoon clouds, no precipitation, moderate wind from the northwest with gusts to 60 km/h, treeline temperatures around -10 C.

THURSDAY: Cloudy, light flurries with up to 5 cm of low density snow, moderate wind from the northwest with some gusts to 50 km/h, treeline temperatures around -8 C.

FRIDAY: Mostly sunny skies, light wind from the north with gusts to 40 km/h, treeline temperatures around -10 C.

Avalanche Summary

Over the past few days there have been some reports of small (size 1) loose dry avalanches (sluffs) and some small isolated wind slab avalanches. This could change on Wednesday if wind speeds increase and form fresh thicker wind slabs.

Snowpack Summary

With plenty of soft, light snow available for transport, expect wind slab formation at upper elevations if wind speed pick up. A northwesterly wind direction means atypical cross-loading and reverse loading patterns. 20-40 cm now sits over a freezing rain crust below 1500 m and above this elevation it may rest on a layer of large surface hoar crystals. Our field team reported easy shears on this layer in their MIN report last week. The lower snowpack is generally well bonded.

Terrain and Travel

  • Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
  • Avoid freshly wind loaded terrain features.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
  • Sheltered slopes at lower elevations will offer the best riding.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

Problems

Wind Slabs

An icon showing Wind Slabs

With plenty of soft, light snow available for wind transport, we expect to see wind slab formation in the alpine and open areas near treeline. A north or northwest wind means atypical cross-loading and reverse loading patterns. Be especially cautious near ridgetops.

Aspects: North East, East, South East, South, South West, West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 29th, 2021 4:00PM

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