Avalanche Forecast
Issued: Mar 19th, 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.
jsmith,
Avalanche Canada
Lingering wind slabs may remain reactive to human triggers in isolated locations at upper elevations.
Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Summary
Confidence
Avalanche Summary
A naturally triggered size 2 wind slab was reported on a north aspect in the alpine on Saturday.
Additionally, two natural and numerous explosive triggered cornice falls up to size 2.5 were reported on north aspects in the alpine. None of them triggered slabs on the slopes below.
A remotely triggered size 2 storm slab avalanche was reported on a north aspect in the alpine on Friday. The slab was 30-40 cm deep and failed on a crust. See MIN.
Snowpack Summary
Expect to find a melt-freeze crust on the surface of all aspects at treeline and below and on sunny aspects in the alpine. Solar radiation will break down the crust on sunny slopes throughout the day.
Lingering wind slabs may remain reactive to human triggers in isolated locations at upper elevations.
30-50 cm down there is a sun crust on sunny aspects and surface hoar (3-10 mm) on isolated shady and sheltered slopes.
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
Partly cloudy / 20 km/h east ridgetop wind / Temperature at treeline around -6 C / Freezing level valley bottom
Monday
Mix of sun and cloud / 20 km/h northeast ridgetop wind / Temperature at treeline around -3 C / Freezing level 1700 m
Tuesday
Sunny / 10 km/h north ridgetop wind / Temperature at treeline around -3 C / Freezing level 1700 m
Wednesday
Sunny / 10 km/h north ridgetop wind / Temperature at treeline around 0 C / Freezing level 2000 m
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
- A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Cornice failure may trigger large avalanches.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Problems
Wind Slabs
Lingering wind slabs may remain reactive to human triggers in isolated locations at upper elevations.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
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 20th, 2023 4:00PM
