Avalanche Forecast
Issued: Feb 18th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
jpercival,
Avalanche Canada
Storm slab avalanches are present on all aspects. Carefully evaluate the snowpack for slab properties as you move through the terrain and investigate the bond to the crust below.
Avalanches are likely to begin forming on wind-loaded features in the alpine. Continually assess conditions as they change through 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 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 48 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
Saturday Night
Mainly cloudy with very light isolated flurries, 1 to 5 cm of accumulation. Winds northwest 10 km/h gusting to 50 km/h. Treeline temperatures -4 °C and freezing levels 900 m.
Sunday
Cloudy with light isolated flurries, 5 to 10 cm of accumulation. Winds northwest 40 km/h gusting to 60 km/h. Treeline temperatures -3 °C and freezing levels 1000 m.
Monday
Cloudy with moderate to heavy snowfall, 10 to 30 cm accumulation. Winds northwest 40 km/h gusting 60 km/h. Treeline temperature 0 °C. Freezing level 1500 m.
Tuesday
Clearing with very light isolated flurries, trace amounts of accumulation. Winds north 30 km/h. Treeline temperature -6 °C. Freezing level 400 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
Storm Slabs
Storm snow sits above a hard melt-freeze crust, which may take time to bond. Back off steep slopes until they've had time to stabilize. Be especially cautious where winds have redistributed snow into deep pockets in lees, watch for an increase in slab properties and reactivity.
Expect as northerly winds increase that new winds slabs will begin to form and build on south-aspect slopes.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 19th, 2023 4:00PM
