Avalanche Forecast
Issued: Mar 7th, 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.
zryan,
Avalanche Canada
Don't let good riding lure you into dangerous terrain. Avoid exposure to cornices and look to sheltered and shaded terrain for the best and safest riding.
Triggering large slab avalanches remains possible in steep, rocky, and wind-affected areas.
Summary
Confidence
Moderate
Avalanche Summary
Last weekend, several natural and human-triggered wind slabs were observed from a variety of aspects in alpine and treeline terrain as northeasterly winds impacted the region. Check out this MIN from Pine Pass on Saturday for an example.
Another MIN report from Pine Pass on Sunday shows a very large deep persistent slab from alpine terrain that was likely triggered by a cornice failure or wind-loading. This is the first observation in several weeks of deep persistent slab activity and is an indication that this layer should be on our radar, particularly in the shallower snowpack parts in the region.
Thank you for all the great MIN posts! Please keep sharing your observations on the Mountain Information Network.
Snowpack Summary
Shifting winds have redistributed last week's storm snow into wind slabs on a variety of aspects while soft snow remains in sheltered areas. Storm snow overlies heavily wind-affected snow.
The middle of the snowpack is generally strong.
A weak layer of large and weak facets is found near the base of the snowpack. This layer is of greatest concern in shallow snowpack areas in the north and east of the region.
Weather Summary
Tuesday night
Mainly cloudy with flurries, up to 5 cm of accumulation. Alpine temperatures drop to a low of -10 C. Ridge wind southeast 20 to 45 km/h. Freezing level at valley bottom.
Wednesday
A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of -8 C. Ridge wind southeast 30 to 50 km/h. Freezing level at valley bottom.
Thursday
Sunny with cloudy periods and isolated flurries. Alpine temperatures reach a high of -7 °C. Ridge wind southwest 15 to 35 km/h. Freezing level at valley bottom.
Friday
A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of -10 C. Ridge wind southeast 30 to 50 km/h. Freezing level at valley bottom.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- 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.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
Problems
Wind Slabs
Variable winds over the past week mean that wind slabs could be found on all aspects.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A weak layer of facets exists near the base of the snowpack. Large triggers such as smaller avalanches in motion or cornice failures have the potential to produce very large avalanches with wide propagation. Suspect terrain for human triggering includes steep, shallow and rocky terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 8th, 2023 4:00PM
