Avalanche Forecast

Issued: Jan 25th, 2023 4:00PM

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

Avalanche Canada mbender, Avalanche Canada

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High consequence persistent and deep persistent slab avalanches have been reported every day over the past week. Stick to low angle terrain away from any overhead hazard.

Read more in our latest forecaster blog.

Summary

Confidence

Low

Avalanche Summary

Both natural and human triggered persistent and deep persistent slab avalanches continue to be reported everyday through the past week. On Wednesday there was a report of a remotely triggered (from a distance) size 2 persistent slab avalanche at treeline on a south aspect. There was also a size 3 naturally triggered deep persistent slab avalanche with a wide propagation reported on a south aspect in the alpine.

On Monday a fatal 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.

Last Saturday a fatal avalanche Incident occurred in the Oasis riding area south of Valemont. This avalanche resulted in a rider fatality. This was a remotely triggered (from a distance) size 2.5 deep persistent slab avalanche on a north-northwest aspect at 2100 m. More details can be found here.

This MIN describes a close call on Sunday.

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 low-consequence terrain that has been heavily trafficked throughout the winter. Stay disciplined and adjust your expectation for this winter.

Snowpack Summary

New snow continues to gradually accumulate. West and north 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.

A prominent layer of buried surface hoar can be found roughly 50 to 90cm deep. It is found in some places but not in others, but has shown ongoing signs of instability in many parts of the region.

Large, weak facets buried in November can be found 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

Wednesday Night

Mainly cloudy with scattered flurries, accumulation 3-5cm. Ridge wind northwest 30-60 km/h. Alpine temperature -3 C. Freezing level 1400 m.

Thursday

Cloudy with scattered flurries, accumulation 3-5 cm. Ridge wind northwest 40 km/h. Alpine temperature -4 C. Freezing level 1500 m.

Friday

Mainly cloudy with isolated flurries. Ridge wind north 15-30 km/h. Alpine temperature -8 C. Freezing level valley bottom.

Saturday

Mainly sunny. Ridge wind northeast 30 km/h. Alpine temperature -15 C.

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.
  • Remote triggering is a concern, watch out for adjacent and overhead slopes.
  • Storm slabs in motion may step down to deeply buried weak layers resulting in very large avalanches.

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.

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.

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 have formed 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.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - 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 openings treeline and below.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Jan 26th, 2023 4:00PM

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