Avalanche Forecast

Archived

Jan 26th, 2023–Jan 27th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Cariboos, North Rockies, Blue River, Clearwater, McBride, Premier, Quesnel, Sugarbowl, Clemina, North Monashee, McGregor, Renshaw, Robson.

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.

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. 20-60 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 50-90 cm 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

Upslope conditions Thursday night into Friday may produce larger snowfall accumulations on the eastern slopes of the Monashees and Cariboos. Isolated hot spots around Bowron Lakes, the Highway 5 corridor, and Valemount, could accumulate upwards of 20 cm by 4 pm Friday.

Thursday night

Cloudy with isolated flurries, 5-10 cm. Ridge wind northwest 10-20 km/hr. Alpine low temperature -6 C. Freezing level dropping to valley bottom.

Friday

Continued scattered flurries, 5-10 cm. Ridge wind north 15-25 km/hr. Alpine temperature -8 C. Freezing level valley bottom.

Saturday

Isolated flurries clearing into blue skies. Ridge wind northeast 10-20 km/hr. Alpine temperature -15 C.

Sunday

Sunny. Ridge wind northeast 5-15 km/hr. Alpine temperature -20 C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for fresh storm slabs building throughout the day.
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.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.