Avalanche Forecast
Issued: Dec 21st, 2024 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
Avalanche Canada,
Avalanche Canada
When the snowpack is the question, terrain is the answer.
Uncertainty necessitates conservative terrain selection and good travel habits.
Summary
Confidence
Moderate
Avalanche Summary
A widespread natural avalanche cycle took place during the storm last Wednesday. Following this storm, the most notable avalanche activity has been large (size 2) persistent slab avalanches failing on buried crust/facets or surface hoar.
On Saturday in the Goat Range, a size 2 avalanche was remote triggered from 100 m away! Remote-triggered avalanches are a strong sign of an unstable snowpack.
Snowpack Summary
Up to 15 cm of new snow will add to 60 cm of recent storm snow. Southwest winds have redistributed this snow into deeper deposits in lee terrain features at higher elevations.
In the mid snowpack (down 40 to 100 cm) there are weak layers of facets, crusts, and in some places surface hoar. The distribution of these layers is highly variable throughout the region. The areas showing the greatest reactivity in these layers are the Goat Range, Bonningtons, and Rossland Range.
The lower snowpack is strong and bonded. Treeline snow depths range from 100 to 180 cm.
Listen to Friday night's State of the Snowpack for more details.
Weather Summary
Saturday Night
Cloudy with 5 to 15 cm of new snow. 20 to 50 km/h southwest ridgetop wind. Treeline temperature -4 °C.
Sunday
Cloudy with up to 2 cm of new snow. 15 to 30 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Monday
Cloudy with up to 5 cm of new snow. 15 to 40 km/h southwest ridgetop wind. Treeline temperature -4 °C.
Tuesday
Cloudy with up to 15 cm of new snow. 20 to 50 km/h southwest ridgetop wind. Treeline temperature -3 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Approach steep and open slopes at and below treeline cautiously, as buried surface hoar may exist.
- Surface hoar distribution is highly variable. Avoid generalizing your observations.
- Be aware of the potential for large avalanches due to a buried crust.
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
Problems
Persistent Slabs
Surface hoar, and in some areas facets over a crust, have produced large avalanches and shown reactivity in tests in the past few days. Be especially cautious in steep openings at treeline and below.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
New snow and wind are expected to form fresh, reactive wind slabs at upper elevations.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 22nd, 2024 4:00PM
