Avalanche Forecast
Issued: Mar 16th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
mbender,
Avalanche Canada
Wind slabs at upper elevations are the main concern. Minimize your exposure to steep slopes facing the sun during the hottest part of the day.
Summary
Confidence
High
Avalanche Summary
On Thursday in the Elk Valley there were reports of several size 3 explosives triggered wind slab avalanches that stepped down to a deeply buried weak layer of facets. These avalanche were triggered at the upper end of treeline and in the alpine and were mostly in cross-loaded terrain features on west and northwest aspects.
On Wednesday, a skier accidental size 2 wind slab avalanche was triggered near St. Mary's. The avalanche occurred on a northeast aspect at treeline and stepped down to the basal facets. For photos and more details check out the MIN report.
If you head out in the backcountry, let us know what you are seeing by submitting a report to the Mountain Information Network.
Snowpack Summary
20-40 cm of wind-affected storm snow falling earlier in the week can be found above 1400 m. The storm snow sits on a thin sun crust on solar slopes and wind affected snow in open areas. Below 1400 m a rain crust covers the surface.
In the Purcells, several weak layers from Jan and Feb can be found down 50 to 120 cm however they are showing signs of strengthening. The mid-snowpack is generally well-settled.
The lower snowpack is made up of a widespread layer of large, weak basal facets and depth hoar in some areas. this weakness has been responsible for a number of recent very large, destructive avalanches and will continue to be a concern.
Weather Summary
Thursday Night
Cloudy with clear periods. Treeline temperature -7 °C. Wind light southwest.
Friday
Mainly sunny. Treeline temperature 0 °C. Wind light southwest. Freezing level rising to 1800 meters.
Saturday
Mainly sunny. Treeline temperature 1 °C. Wind light southwest. Freezing level rising to 2000 meters.
Sunday
Mainly sunny. Treeline temperature 0 °C. Wind light southwest. Freezing level rising to 1900meters.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be especially cautious as you transition into wind affected terrain.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- Avoid exposure to steep, sun exposed slopes, especially when the solar radiation is strong.
- Avoid rock outcroppings, convexities, and anywhere the snowpack is thin and/or variable.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Strong southwest winds and 20-40 cm of recent dense storm snow have built wind slabs in alpine and treeline lees. Although natural avalanche activity has tapered off wind slabs remain possible to human trigger.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The base of the snowpack remains very weak. Very large human triggered avalanches are possible at treeline and above.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 17th, 2023 4:00PM
