Avalanche Forecast
Issued: Feb 19th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
jpercival,
Avalanche Canada
Wind slabs are forming over a melt-freeze crust on all aspects in both the alpine and treeline. Continually assess conditions as increasing wind and snowfall will incur rapid change throughout the day.
Carefully evaluate wind loading as you move through the terrain and investigate the bond of newly formed wind slabs to the crust below.
Summary
Confidence
Avalanche Summary
On Saturday, small (size1) windslabs were triggered during travel on skis. These windslabs were located on north aspect terrain near 1600 m elevation.
On Friday, explosive control work on the north shore produced 3 small (size 1.5) storm slab avalanches, crowns were estimated between 20 and 40 cm in depth and one ran 100 m in length. Additionally, reports of small (size 1) storm slabs found on all aspects, were triggered during ski cutting at north shore professional operations. Slab properties within the recent storm snow began to present mid-day, as temperatures rose slightly. These slab avalanches ran on a previously well-established melt-freeze crust and were 30 cm in depth.
Snowpack Summary
A storm has delivered nearly 40 cm of new snow over the past 72 hr period. This new snow has accumulated over a variety of surfaces including thin wind slabs in the alpine, small surface hoar in sheltered areas and a breakable freezing rain crust between 1100 m and 1600 m.
A hard crust is found 60 to 80 cm deep. Below this, the mid and lower snowpack is well-settled, strong, and consolidated.
Snowpack depths are reaching 250 cm at treeline.
Weather Summary
Sunday Night
Cloudy with light isolated flurries, 1 to 5 cm of accumulation. Winds northwest 60 km/h gusting to 80 km/h. Treeline temperatures -1 °C and freezing levels 1200 m.
Monday
Cloudy with moderate to heavy snowfall beginning in the late afternoon, 10 to 30 cm accumulation. Winds northwest 40 km/h gusting 80 km/h. Treeline temperature 0 °C. Freezing level 1500 m.
Tuesday
Clearing with light isolated flurries, 1 to 5 cm of accumulation. Winds north 30 km/h easing to 10 km/h. Treeline temperature -6 °C. Freezing level 400 m.
Wednesday
Mostly clear with no forecast precipitation. Winds northeast 20 km/h. Treeline temperature -9 °C. Freezing level 0 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Carefully evaluate steep lines for wind slabs.
- Wind slabs are most reactive during their formation.
- Use increased caution at all elevations. Storm snow is forming touchy slabs.
Problems
Wind Slabs
North winds will become westerly and will reach velocities in excess of 60 km/h. Expect the 40-plus centimeters of available snow to transport to the South through to east aspect terrain and slopes. This new windslab will overlie a well-established melt-freeze crust and be sensitive to light triggers such as skiers.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 20th, 2023 4:00PM
