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 Wind Slabs and Deep Persistent Slabs.
jsmith,
Avalanche Canada
Strong northeasterly winds have formed fresh wind slabs on lee aspects in the alpine.
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Summary
Confidence
High
Avalanche Summary
A cornice triggered size 3 deep persistent slab avalanche was reported on the northeast face of Mt. Mackenzie on Thursday. See MIN.
Explosive control work on Thursday triggered wind slabs up to size 2 on steep, wind loaded alpine slopes.
One explosive triggered size 2.5 was reported east of Revelstoke on a wind loaded, large alpine slope. It released on weak layer around 100 cm deep.
Snowpack Summary
Sun crust on sunny slopes and surface hoar (3-10 mm) on shady slopes at all elevations. Previous wind effect in open areas at treeline and above.
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 rounding but there is still a considerable step in resistance between them and the overlying snow. These facets are most pronounced in shallow rocky areas.
Weather Summary
Friday Night
Cloudy with isolated flurries; 0-5 cm / Light southwest ridgetop wind / Low temperature at treeline around -10 C / Freezing level valley bottom.
Saturday
Cloudy with flurries; 3-10 cm / Light southwest ridgetop wind / High temperature at treeline around -3 C / Freezing level 1000 m.
Sunday
Mostly cloudy with isolated flurries; 3-5 cm / Light south ridgetop wind / High temperature at treeline around -2 C / Freezing level 1300 m.
Monday
Snow; 10-20 cm / Strong southwest ridgetop wind / High temperature at treeline around 1 C / Freezing level rapidly rising to 1800 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
- Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
Problems
Wind Slabs
Strong northeasterly winds have formed fresh wind slabs on lee aspects in the alpine.
Aspects: South East, South, South West, 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 11th, 2023 4:00PM
