Avalanche Forecast
Issued: Dec 28th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
jleblanc,
Avalanche Canada
There is a Special Public Avalanche Warning in effect for this region. Learn more: avalanche.ca/spaw
Slabs are now primed to release and smaller avalanches may trigger buried weak layers producing large avalanches. It's a good time to play it conservatively.
Summary
Confidence
Avalanche Summary
A natural cycle occurred with numerous recent avalanches in most avalanche paths. In the Kokanee range, large persistent slabs (size 2.5-3) were reported on Tuesday. One of them was remotely triggered by a vehicle on a reloaded bed surface. Others were naturally triggered and stepped down to deeper buried weak layers. Smaller storm slabs avalanches were accidentally human-triggered around Revelstoke and in the Esplanade range.
Please continue to share any observations or photos on the Mountain Information Network.
Snowpack Summary
Between 30 and 60 cm of moist dense storm snow is now sitting on previous surfaces, varying from sugary faceted grains, cold unconsolidated snow or a small surface hoar. At higher elevations, new snow has been redistributed on northerly aspects and fresh slabs may not bond well to older surfaces. At lower elevations, a significant rain crust can be found.
In the upper snowpack, up to three weak layers created earlier in December can be found. Some of these may not exist in all areas of our region. The November weak layer, which will continue to be a concern even after this warm-up, can be found anywhere between 75 and 125 cm down. The bottom of the snowpack is generally weak and faceted.
Weather Summary
A low-pressure system will bring light snowfalls to the Monashees and Selkirks Wednesday night. A new Pacific frontal system will push over the interior late Thursday afternoon. A very gradual cooling trend begins with unsettled conditions.
Wednesday night
Cloudy, light snowfalls 2-5 cm, southwesterly ridge winds up to 20 km/h, treeline temperatures -8°C. Freezing level returning to valley bottom.
Thursday
Mostly cloudy, scattered flurries up to 2 cm, southwesterly ridge winds up to 30-40 km/, treeline temperatures -6 °C. Freezing level around 500 m.
Friday
Cloudy, snow 5-10 cm, southerly ridge winds up to 40 km/, treeline temperatures -6°C.
Saturday
Cloudy, isolated flurries, southerly ridge winds up to 20 km/, treeline temperatures -8 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Good day to make conservative terrain choices.
- Be carefull around freshly wind loaded features.
- Choose simple, low-angle, well supported terrain without convexities.
Problems
Storm Slabs
Warm temperatures and continued snowfall are adding depth and load to the reactive storm slab. These storm slabs will remain reactive for longer than “typical” considering it is overlying a widespread weak layer. If triggered, storm slabs in-motion may step down to deeper layers and result in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Three weak layers are buried at a prime depth for human triggering within the top meter of the snowpack. With a snowpack such as this, it is important to keep a heads up and know that very small avalanches can quickly become very large. Check out our forecaster blog to learn about how to manage persistent slab problems.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 29th, 2022 4:00PM
