Avalanche Forecast
Issued: Mar 11th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs and Wind Slabs.
zryan,
Avalanche Canada
Diligently maintain a conservative mindset. You may not see signs of instability on the surface however the deep persistent weak layer remains a major concern at the bottom of the snowpack.
Keep in mind that even short periods of sun can have a significant impact. Give steep solar slopes and overhead cornices a wide berth during periods of strong solar radiation.
Summary
Confidence
Avalanche Summary
No recent avalanches have been reported in this region.
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
5 to 15 cm of low-density new snow has been redistributed by northeast winds into pockets of wind slab in exposed areas. This new snow overlies hard wind-affected surfaces in open areas, a sun crust on steep solar aspects, and facetted snow in sheltered areas.
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
Saturday night
Clear periods. Alpine temperatures drop to a low of -11 °C. Ridge wind light from the southwest. Freezing level at valley bottom.
Sunday
Cloudy with sunny periods and isolated flurries. Alpine temperatures reach a high of -5 °C. Ridge wind 15 to 40 km/h from the southwest. Freezing level rises to 1300 meters.
Monday
Cloudy with mixed precipitation, up to 10 cm of new snow accumulation at upper elevations. Alpine temperatures reach a high of 0 °C. Ridge wind 30 to 60 km/h from the southwest. Freezing level rises to 2000 meters.
Tuesday
A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of -3 °C. Ridge wind 15 to 45 km/h from the southwest. Freezing level rises to 1700 meters.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- Use conservative route selection and resist venturing out into complex terrain.
- Carefully evaluate steep lines for wind slabs.
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
Problems
Deep Persistent Slabs
The base of the snowpack remains very weak. Very large human triggered avalanches are possible at treeline and above. Avoid shallow and rocky areas, where the snowpack depth is highly variable. This is a very concerning avalanche problem and should stay in your mind when traveling in the backcountry.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Friday's northeast wind and 5-15 cm of new snow may have formed small but reactive wind slabs most likely found on southwest-facing slopes. Wind slabs may bond poorly to the underlying crust.
Aspects: North, South East, South, South West, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 12th, 2023 5:00PM
