Avalanche Forecast
Issued: Jan 25th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs, Wind Slabs and Persistent Slabs.
mbender,
Avalanche Canada
The main concern remains with several buried weak layers that continue to produce high consequence avalanches. Stick to low angle terrain away from any overhead hazard.
Summary
Confidence
Moderate
Avalanche Summary
On Monday, a fatal skier-triggered avalanche incident occurred in the Selkirk range 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 was a size 2 with a crown depth of 50 cm.
Numerous natural and human-triggered wind slabs were also observed on Sunday through Tuesday throughout the region, ranging in size from 1.5 to 2.5. One of these avalanches in the south of the region resulted in a partial burial. These avalanches mainly occurred on east and northeast aspects in the alpine and treeline.
High consequence avalanche activity has been ongoing for several weeks. Your best defence is to stay diligent in choosing low-consequence terrain. Stick to slopes that have been heavily trafficked throughout the winter and avoid venturing into untouched zones. Stay disciplined and adjust your expectation for this winter.
Snowpack Summary
New snow continues to gradually accumulate. A layer of surface hoar may be found below 5-15cm of recent snowfall as well as a sun crust on steep solar aspects. At lower elevations, a rain crust exists down 10 to 40cm, with reported elevations extending up to 1700 m around Revelstoke and closer to 2000 m further south.
Two persistent weak layers in the middle of the snowpack may remain reactive to human triggering. They are both surface hoar layers that formed in early January and are typically found 40 to 90 cm deep throughout the region. There are also some deeper facet and surface hoar layers that formed in December, but recent snowpack observations suggest they are strengthening.
The bottom of the snowpack is made up of large weak facets buried in late November, which has caused a deep persistent slab problem for this region.
Weather Summary
Wednesday Night
Mainly cloudy with isolated flurries. Ridge wind northwest 30-60 km/h. Alpine temperature -4 C. Freezing level 1400 m.
Thursday
Mostly cloudy with isolated flurries. Ridge wind northwest 30-60 km/h. Alpine temperature -2 C. Freezing level 1500 m with a temperature inversion possible.
Friday
Mainly cloudy with flurries. Ridge wind northwest 15-40 km/h. Alpine temperature -6 C. Freezing level 500m.
Saturday
Mainly sunny. Ridge wind northeast 30 km/h. Alpine temperature -10 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.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. This layer has most recently been problematic 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
Expected Size
Wind Slabs
Northwesterly winds will continue to form fresh wind slabs in the alpine and treeline.
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Numerous problematic weak layers exist in the top meter of the snowpack, with recent observations suggesting the most likely of these to trigger are surface hoar layers found 40 to 90cm deep. Be especially cautious around steep convex openings at treeline and below.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 26th, 2023 4:00PM
