Avalanche Forecast

Issued: Feb 8th, 2023 4:00PM

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

Avalanche Canada lbaker, Avalanche Canada

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Continue to choose conservative terrain and watch for clues of instability as storm snow and strong winds continue to incrementally load the snowpack throughout the day.

Avoid lee and cross-loaded terrain. Minimize exposure to avalanche terrain during times of heavy loading from wind and new snow.

Summary

Confidence

Moderate

Avalanche Summary

On Tuesday, a skier accidental, size 1.5 storm slab avalanche was reported at 1500 m. A size 2, natural windslab avalanche was observed on a northwest aspect at 1400 m.

On Monday, a natural wind slab avalanche, size 2 was observed on a northerly aspect at 1900 m.

On Sunday, three very large natural avalanches were observed up to size 4. Two were size 3 persistent slab avalanches on steep north-facing aspects with 750 m wide crowns. A size 3.5-4 deep persistent slab avalanche was also observed. It is suspected this avalanche failed in depth hoar at the base of the snowpack.

See more on the potential of triggering deeper weak layers in our latest Forecasters' Blog.

Snowpack Summary

Flurries begin again Thursday morning building upon 60 to 110 cm of storm snow from the last week. The storm snow sits on previously wind-affected surfaces. Below this, a melt-freeze crust is found on sun-exposed slopes and everywhere below 1600 m.

Several crust/facet/surface hoar layers exist in the upper and middle portions of the snowpack. The most concerning persistent weak layer is at the base of the snowpack from large and weak facets formed in November. This layer is widespread and most likely problematic in steep, rocky alpine and upper treeline terrain.

Weather Summary

Wednesday Night

Partly cloudy. Ridge wind southwest 40-50 km/h. Alpine temperatures -10 C. Freezing level valley bottom.

Thursday 

Partly cloudy with scattered flurries, 5-10 cm through most of the region. Up to 20 cm accumulation in the Pine Pass area. Ridge wind from the southwest 50 km/h picks up to 70 km/h in the evening. Alpine temperatures rise to -3 C. Freezing level 1400 meters. 

Flurries continue through the night, 5-10 cm accumulation

Friday

Partly cloudy with isolated flurries, 5-10 cm accumulation. Alpine temperatures rise to -2 C. Ridge wind southwest 40-50 km/h. Freezing level 1300 meters. 

Saturday

Partly cloudy with isolated flurries, 5-10 cm accumulation. Alpine temperatures rise to -3 C. Ridge wind southwest 40-50 km/h. Freezing level 1000 meters. 

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.
  • Avoid all avalanche terrain during periods of strong wind.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Problems

Wind Slabs

An icon showing Wind Slabs

Flurries begin again Thursday morning, slowly adding more load to the snowpack once again. In all exposed areas, new snow and strong southwesterly winds are building deep pockets in less that are reactive to natural and human triggers. Avoid lee and cross-loaded slopes.

If triggered wind slab avalanches may step-down to deeper weak layers and initiate large and destructive avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

A layer of large and weak facets sits near the base of the snowpack. This layer is most prominent in upper treeline and lower alpine elevations. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain. This layer has recently produced very large natural avalanches see avalanche summary for more information. Your best defence is to stay diligent in choosing low-consequence terrain away from overhead exposure.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Persistent Slabs

An icon showing Persistent Slabs

Recent large persistent slab avalanche observations are strong evidence that these layers are still an active concern in this region. Numerous problematic weak layers exist in the top meter of the snowpack. Be cautious around steep openings within and near treeline elevations as active loading continues.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3.5

Valid until: Feb 9th, 2023 4:00PM