Avalanche Forecast
Issued: Dec 27th, 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.
rgoddard,
Avalanche Canada
There is a Special Public Avalanche Warning in effect for this region. Learn more: avalanche.ca/spaw
Warm temperatures and continued snowfall will keep the avalanche hazard elevated.
Slabs are now primed to release and smaller avalanches may trigger buried weak layers producing large avalanches. If you start to see natural avalanche activity consider a heightened danger rating.
It's a good day to play it conservatively.
Summary
Confidence
Moderate
Avalanche Summary
Snow that has been falling since Friday and a warming trend that started on Monday continues conditions for avalanche activity.
The majority of these avalanches have occurred naturally from the storm snow. There have been a number of small and large avalanches that people have triggered accidentally. Again these have occurred from storm slabs but several large avalanches that were accidentally human-triggered and slid on buried weak layers.
Slab reactivity is expected to increase in the storm snow as well as the multiple buried weak layers buried beneath.
Snowpack Summary
Warm temperatures and moist snow have promoted slab properties in the top layer of the snowpack. Another 10 to 15 cm will add to this process. Before the warming trend that started on Monday, the top 50 to 75 cm of the snowpack was fairly unconsolidated. Strong southwest winds will have redistributed much of this snow at higher elevations, where it may be cooler, into fresh wind slabs. Slabs that are formed may not bond well to older surfaces.
There are up to three weak layers created earlier in December. Some of these may not exist in all areas of our region. The November weak layer, which will continue to be a concern in this warm-up, can be found anywhere between 75 and 125 cm down. The bottom of the snowpack is generally weak and faceted.
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.
Weather Summary
Tuesday Night
Cloudy, 4 to 10 cm accumulation, 20 km/h southwest wind, treeline temperatures -5 to -2 °C.
Wednesday
Mostly cloudy, up to 6 cm accumulation, 10 to 20 km/h southwest wind, treeline temperatures -5 °C.
Thursday
Mostly cloudy with sunny periods in some areas, 0 to 5 cm accumulation, 20 to 30 km/h southeast wind, treeline temperatures -10 to -5 °C.
Friday
Cloudy, up to 6 cm accumulation, 25 km/h south wind, treeline temperatures -10 to -5 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Good day to make conservative terrain choices.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Be carefull around freshly wind loaded features.
Problems
Storm Slabs
Warm temperature and continued snowfall are adding depth and load to our storm slab.
At higher elevation, cooler temperatures and southwest winds may have produced wind slabs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Three weak layers are buried at a prime depth for human triggering within the top metre of the snowpack. Rain, wet snow, and warm temperatures will increase load on these layers making large avalanches a possibility.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 28th, 2022 4:00PM
