Avalanche Forecast

Issued: Jan 24th, 2023 4:00PM

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

Avalanche Canada zryan, Avalanche Canada

Email

Avoid avalanche terrain. Dangerous avalanche conditions exist in this region.

Wind and warming will continue to test a fragile snowpack. Read more in our latest forecaster blog.

Summary

Confidence

Low

Avalanche Summary

On Monday in the neighbouring region to the south, a serious skier-triggered avalanche incident occurred in the Selkirks near Revelstoke. The avalanche was on an east aspect at 1900 m. It occurred on a steep, unsupported open slope below treeline and failed on a weak layer of surface hoar buried in early January. This large avalanche (size 2) had a crown depth of 50 cm. Details are still emerging about this event.

Also on Monday, several natural wind slabs (size 1-2) and a few natural deep persistent slabs (size 2-3) were reported. These avalanches occurred in the alpine in wind-loaded terrain.

On Saturday a serious avalanche Incident occurred, which resulted in a fatality, occurred in the Oasis riding area south of Valemont. The avalanche was on a north-northwest aspect at 2100 m. It was remotely triggered and ran on the November facets near the bottom of the snowpack. This large avalanche (size 2.5) had a depth of 80 to 120 cm. There were several other reports of human-triggered avalanches from nearby areas.

This MIN describes a close call on Sunday.

All of these very large avalanches occurred at upper treeline/lower alpine. Avalanches like these are most likely to be triggered on steep, shallow and previously undisturbed slopes. Your best defence at this time is to stay diligent in choosing conservative and low-consequence terrain. Stick to slopes that have been heavily trafficked throughout the winter and avoid venturing into untouched zones. Adjust your goals to match conditions. This is not a time to tick off objectives, but rather to enjoy lower-angled riding, spend time outdoors with friends, and get exercise in the outdoors. Stay disciplined and adjust your expectation for this winter.

Snowpack Summary

New snow continues to gradually accumulate. Westerly winds will continue to affect exposed terrain and form wind slabs near ridgetops. 20 to 60 cm of recent snowfall sits above a layer of surface hoar as well as a sun crust on steep solar aspects. At lower elevations, recent snow is accumulating above a rain crust.

A prominent layer of buried surface hoar can be found roughly 40 to 80cm deep. It is spotty in nature but has shown ongoing signs of instability in many parts of the region.

Large, weak facets buried in November are widespread at the base of the snowpack. This layer has been most problematic to date in thin, rocky areas in the alpine and treeline.

Weather Summary

Tuesday night

Mainly cloudy with flurries, less than 5 cm accumulation with isolated areas up to 10 cm. Alpine temperatures rise to -4 C. Ridge wind northwest 30- 60 km/h. Freezing level rises to 1400 m.

Wednesday

Mainly cloudy with isolated flurries. Alpine temperatures rise to -1 C. Ridge wind northwest 30-80 km/h. Freezing level rises to 1600 m.

Thursday

Cloudy with flurries, up to 5 cm of accumulation. Alpine temperatures around -3 C. Rdige wind northwest 40-90 km/h. Freezing level remains elevated around 1500 m.

Friday

A mix of sun and cloud with flurries. Alpine temperatures drop to -8 C. Ridge wind northwest 25-50 km/h. Freezing level drops to 500 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be mindful that deep instabilities are still present and have produced recent large avalanches.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
  • Storm slabs in motion may step down to deeply buried weak layers resulting in very large avalanches.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

Problems

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 has most recently been reactive in upper treeline/lower alpine elevations.

Avoid thin and rocky start zones where weak layers sit closer to the surface, riders are most likely to trigger an avalanche on this layer in steep, shallow previously undisturbed terrain or by first triggering a layer further up in the snowpack.

Remote triggering is a concern for this layer, avoid travelling below steep slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3.5

Storm Slabs

An icon showing Storm Slabs

New snow and west winds are expected to form fresh, reactive storm slabs that will be deepest in wind-loaded terrain at upper elevations. Reports suggest that the new snow overlies surface hoar in some areas. We'd be particularly suspect of sheltered areas at treeline where this weak layer is most likely to be preserved.

Keep in mind the very real potential of these slabs stepping down to deeper instabilities creating large and consequential avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1.5 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

A reactive surface hoar layer is found 40 to 70 cm deep throughout the region. Be especially cautious around steep convex openings at treeline and below. Remote triggering is also a concern for this layer.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Jan 25th, 2023 4:00PM