Avalanche Forecast

Issued: Dec 28th, 2021 3:00PM

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

Avalanche Canada JSmith, Avalanche Canada

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Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Keep in mind that cold temperatures significantly increase the consequence of even minor injuries in the backcountry.

Summary

Confidence

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Weather Forecast

TUESDAY NIGHT: Partly cloudy / Light north wind / Low of -27

WEDNESDAY: Sunny / Light northwest wind increasing to moderate in the afternoon / High of -20

THURSDAY: Mix of sun and cloud / Light northwest wind / High of -19

FRIDAY: Sunny / Light northeast wind / High of -21

Avalanche Summary

No new avalanches were reported on Monday.

Recent explosive control work near Invermere produced large avalanches (size 2) on the crust formed in early December, found 40-70 cm deep in that area.

Snowpack Summary

Variable wind direction has resulted in redistribution of 20-60 cm of recent snow at upper elevations. The recent snow may sit over a layer of weak surface hoar crystals at treeline and below. 

 

The upper snowpack overlies a substantial crust from early December. This crust is approximately 60-120 cm below the surface, 10-30 cm thick on average, and is present across all aspects to at least 2300 m. A layer of weak facets (sugary snow) has been reported above this crust. Snowpack tests are generally showing hard results on this interface.

A late October facet/crust layer of concern sits at the bottom of the snowpack above 1900m. Although this layer has been trending less reactive, it remains on our radar.

The snowpack depth at treeline is around 120-250 cm. The deepest snowpack can be found in the southern half of the region. 

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent winds have created wind slabs on a variety of aspects and created a lot of variability in the upper snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

A persistent slab problem formed by a crust down 50-120 cm has created a low likelihood, high consequence scenario that is difficult to forecast.

Avoid likely trigger spots such as steep, rocky slopes with a shallow or thin to thick snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Valid until: Dec 29th, 2021 3:00PM