Avalanche Forecast
Issued: Mar 6th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Cornices and Deep Persistent Slabs.
zryan,
Avalanche Canada
Don't let good visibility lure you into dangerous terrain. Wind slabs may exist on a variety of aspects due to recently shifting wind direction. The air is cold but the March sun can be strong so avoid exposure to cornices and watch for signs of warming on steep south aspects. Thin rocky areas will remain a concern for triggering deeply buried weak layers in this complex snowpack.
Summary
Confidence
Avalanche Summary
In the past couple of days, a few natural and skier-triggered wind slabs have been reported from south, southwest and east-facing alpine terrain as northerly winds impacted the region. One large (size 2.5) deep persistent slab was triggered by a cornice failure in very steep north-facing alpine terrain.
Read more about managing the deep persistent slab problem in our latest Forecaster Blog.
Snowpack Summary
On the surface, a sun crust can be found on steep south-facing aspects and surface hoar growth has been reported in sheltered areas. Shifting winds have redistributed recent storm snow into wind slabs on a variety of aspects. This storm snow sits over wind-affected surfaces and a thin sun crust on steep south-facing slopes.
The mid-snowpack is generally well-settled and strong.
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
Monday night
Clear periods. Alpine temperatures drop to a low of -16 °C. Ridge wind light from the southeast. Freezing level at valley bottom.
Tuesday
A mix of sun and cloud. Alpine temperatures reach a high of -13 °C. Ridge wind light from the southeast. Freezing level rises to 500-1000 meters.
Wednesday
Sunny with cloudy periods. Alpine temperatures reach a high of -13 °C. Light ridge wind from the southeast. Freezing level rises to 600-1100 meters.
Thursday
Sunny with cloudy periods. Alpine temperatures reach a high of -14 °C. Ridge wind light from the southeast. Freezing level rises to 1000 meters.
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.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
Problems
Wind Slabs
Variable winds over the past week mean that wind slabs could be found on all aspects.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Minimize your exposure to cornices, they have grown significantly in recent weeks and can trigger large avalanches on the slopes below. Give them respect and a wide birth when you are travelling under them. Be cautious of solar input.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
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 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 7th, 2023 4:00PM
