Avalanche Forecast
Issued: Dec 24th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet and Storm Slabs.
rbuhler,
Avalanche Canada
There is a lot of uncertainty about how the ongoing storm and rainfall are affecting the snowpack, so a cautious approach is advised. It is recommended to avoid steep rain-soaked areas at lower elevations and recently wind-loaded terrain at the highest elevations.
Summary
Confidence
Avalanche Summary
On Friday, ski cutting triggered several size 1 wind slabs which were 20-30 cm deep.
Widespread natural avalanche activity is expected to have occurred on Saturday with heavy snowfall transitioning to rainfall, and a potentially weak bond between the new snow and the old surface.
Snowpack Summary
At most elevations, rain is now expected to be soaking the surface. Before the warming and the switch from snow to rain, the new storm snow buried a highly variable old surface which included an unsupportive sun crust on southern aspects, spotty surface hoar in sheltered terrain, and heavily wind-affected and hard surfaces in wind exposed terrain.
Prior to the storm, a layer of decomposing surface hoar crystals could be found down 70 cm. There is also a layer of weak, sugary facet crystals near the base of the snowpack. During recent testing, both of these layers were producing hard results and there have been no reports of avalanches occurring on these layers. However, the current storm loading will test these layers and there still remains potential for avalanches in motion to step down to these old layers.
Overall, the snowpack continues to present as thin and averaged 130 cm deep at treeline prior to the storm.
Weather Summary
After a bit of a break Saturday night, the next in a series of warm Pacific storm systems is expected to arrive by mid-morning on Sunday. Precipitation is expected to be most intense along the immediate southwest coast and amounts will likely be higher than the values listed below.
Saturday night
Mainly cloudy and dry, moderate to strong SW wind, freezing level dropping to around 1500 m.
Sunday
Precipitation up to around 30 mm, mostly expected to fall as rain, strong to extreme SW wind, freezing level climbing to around 2800 m.
Sunday night and Monday
Precipitation up to around 40 mm, mostly expected to fall as rain, strong to extreme SW wind, freezing level around 2000 m overnight, falling to around 1300 m Monday afternoon.
Monday night and Tuesday
Precipitation up to around 30 mm, currently expected as snow at the highest elevations and rain at lower elevations, strong S-SW wind, freezing level around 1200 m overnight and rising to around 1700 m during the day.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid the alpine during periods of heavy loading from new snow wind and/or rain.
- Keep in mind that wet avalanches can be destructive due to their high density.
- The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
- Minimize exposure during periods of heavy loading from rain.
Problems
Loose Wet
Rain has likely soaked the snow surface at most elevations. Use extra caution on all steep slopes where the snow surface is moist or wet.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
At the highest elevations, the storm snow may still be reactive, especially in wind-loaded terrain features.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Dec 25th, 2022 4:00PM
