Avalanche Forecast
Issued: Mar 10th, 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.
Avoid shallow, rocky, and wind-loaded terrain where triggering slab avalanches is most likely.
Summary
Confidence
Moderate
Avalanche Summary
No recent avalanches have been reported in this region.
On Tuesday, a deep persistent slab avalanche was triggered by a cornice or solar input in extreme, rocky terrain in the Elkford area. See the MIN for a photo.
Snowpack Summary
Up to 15 cm of low-density new snow has accumulated over 40-50 cm of wind-affected snow in the alpine and open treeline. On solar slopes, they overlie a thin sun crust.
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
Friday night
Mainly cloudy with isolated flurries, up to 5 cm of accumulation. Alpine temperatures drop to a low of -13 °C. Ridge wind light from the northeast. Freezing level at valley bottom.
Saturday
A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of -7 °C. Light ridge wind from the southwest. Freezing level rises to 900 meters.
Sunday
A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of -5 °C. Ridge wind 15 gusting to 40 km/h from the southwest. Freezing level rises to 1200 meters.
Monday
Cloudy with mixed precipitation 5-15 cm of new snow accumulation at upper elevations. Alpine temperatures reach a high of 0 °C. Ridge wind 20 to 55 km/h from the southwest. Freezing level rises to 2000 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.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Wind slabs may be poorly bonded to the underlying crust.
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 11th, 2023 4:00PM
