Avalanche Forecast
Issued: Mar 12th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Deep Persistent Slabs.
jsmith,
Avalanche Canada
Forecast snow and wind are expected to trigger large natural avalanches on Monday.
Travel in avalanche terrain is not recommended.
Summary
Confidence
High
Avalanche Summary
Several natural and rider triggered wind slabs up to size 1.5 on northerly aspects in the alpine were reported on Saturday.
Additionally, there was a size 2 cornice failure on a northeast aspect that did not trigger a slab on the slope below.
Forecast snow and wind are expected to form fresh storm slabs that are reactive to human triggers on Monday.
Snowpack Summary
Forecast snow and wind are expected to form fresh storm slabs that are reactive to human triggers.
The storm snow will add to the 10-20 cm of recent snow which overlies a variety of surfaces. These include surface hoar (3-10 mm) on shady slopes at all elevations, wind affected surfaces at treeline and above, and sun crust on sunny aspects.
The mid-snowpack is generally strong but the lower snowpack is a different story.
The November facets are still prominent at the base of the snowpack. They are showing signs of improving but this layer remains a significant concern in rocky, shallow, or thin to thick snowpack areas at treeline and above.
Weather Summary
Sunday Night
Snow; 15-20 cm / Strong southwest ridgetop wind / Low temperature at treeline around -4 C / Freezing level valley bottom
Monday
Snow; 15-25 cm (rain below 1500 m); another 5-15 cm overnight / Strong southwest ridgetop wind / High temperature at treeline around 2 C / Freezing level rapidly rising to 1800 m
Tuesday
Mix of sun and cloud / Light southwest ridgetop wind / High temperature at treeline around -3 C / Freezing level 1200 m
Wednesday
Mix of sun and cloud / Light southwest ridgetop wind / High temperature at treeline around -2 C / Freezing level 1300 m
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
- Stick to non-avalanche terrain or small features with limited consequence.
- Avoid exposure to overhead avalanche terrain, avalanches may run surprisingly far.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Storm Slabs
Forecast snow and wind are expected to form dangerous storm slabs that are reactive to human triggers at all elevations on Monday.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth, but large triggers such as cornice failures or smaller avalanches in motion have the potential to produce very large avalanches with surprisingly wide propagation. Suspect terrain for human triggering includes steep, shallow, and rocky terrain where the snowpack transitions from thin to thick.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 13th, 2023 4:00PM
