Avalanche Forecast
Issued: Dec 4th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Loose Wet.
rgoddard,
Avalanche Canada
Snow and rain with a rising freezing level will create a natural avalanche cycle.
Seek out low-angle terrain free of buried surface hoar.
Summary
Confidence
Moderate
Avalanche Summary
Several size one to two natural and skier-triggered avalanches were reported in our region this past weekend. Many of these were remotely triggered and ran on the buried surface hoar layer. These avalanches occurred at treeline elevation and on all aspects.
This MIN from Saturday does a great job describing conditions and this one from Sunday shows how the buried surface hoar layer getting triggered and causing avalanches.
Snowpack Summary
Around 30 mm of precipitation falling as rain and/or snow will have been added to the snowpack by the end of the day Tuesday. This will add to the up to 40 cm of new snow from this weekend which covered a layer of large surface hoar. On steep south-facing slopes, this surface hoar sits on a thin sun crust. At higher elevations, the weekend's snow will have formed wind slabs on north and east-facing slopes.
The mid-pack is generally well-settled. Lower in the snowpack a crust with sugary facets beneath it can be found 20 cm off the ground.
Weather Summary
Monday Night
Cloudy, 20 to 30 cm accumulation mix of snow and rain highest amounts in the south, alpine winds south 20 to 30 km/h, freezing levels reaching 2500 m.
Tuesday
Cloudy, up to 15 cm accumulation mix of snow and rain in some areas, alpine winds southwest 25 to 35 km/h, freezing level 2000 to 2500 m.
Wednesday
Mostly cloudy, 10 to 20 cm accumulation mix of rain and snow, alpine winds southwest 15 to 25 km/h, freezing level down to 1500 m by end of the day.
Thursday
Cloudy with chance of sunny breaks, up to 15 cm accumulation focused in the southwest, alpine winds southwest 10 to 20 km/h, freezing level 1500 to 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Remote triggering is a concern, watch out for adjacent and overhead slopes.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Minimize exposure during periods of heavy loading from rain.
- Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.
Problems
Storm Slabs
Snow and rain continue to accumulate and create a heavy load on a weak surface hoar layer in many areas. Expect to find reactive storm slabs in areas where it is not raining.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
A mix of snow and rain will make wet loose avalanches likely.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 5th, 2023 4:00PM
