Avalanche Forecast
Issued: Mar 20th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Deep Persistent Slabs and Cornices.
rbuhler,
Avalanche Canada
Lingering wind slabs and cornices remain a concern. Use extra caution during the heat of the afternoon.
This MIN post also has us concerned that a deep persistent slab problem is developing in the region with the warm temperatures. Use extra caution in thin, rocky terrain where triggering a deep weak layer is most likely.
Summary
Confidence
Avalanche Summary
On Sunday, a few natural size 1 loose wet avalanches were observed from steep terrain on solar aspects.
On Saturday, avalanches up to size 2.5 were reported in the Crowsnest South area which included some deep releases. This may be an indication that a deep persistent slab problem may be developing as warmer temperatures cause the upper snowpack to settle and form a slab over the weak layer at the base of the snowpack.
If you have any observations from this data sparse region, especially regarding a potential deep persistent slab problem, let us know what you are seeing by submitting a report to the Mountain Information Network.
Snowpack Summary
The snow surface consists of a sun crust on solar aspects, a rain crust below 1700 m, and wind-affected snow in exposed terrain at higher elevations. Small facets and/or surface hoar may also exist in shaded and wind-sheltered terrain.
A melt-freeze crust with facets above can be found 50 to 120 cm deep. The layer is currently dormant and has not produced any recent avalanche activity in the region but professionals are still tracking it to watch for signs of it waking up.
The weak layer at the base of the snowpack produced some concerning large avalanches on the weekend and we are concerned that it might be becoming a more active problem with the current warm conditions. Caution is recommended in thin, rocky areas, mainly in the alpine but also possibly at treeline in some areas.
Weather Summary
Monday Night
Clear, winds northeast 20-30 km/h, treeline low around -12 °C.
Tuesday
Sunny, winds northeast 10-20 km/h, freezing level reaching around 1700 m.
Wednesday
Sunny, winds northeast 15-30 km/h, freezing level reaching around 2100 m.
Thursday
Mainly sunny, winds southwest 15-30 km/h, freezing level reaching around 1800 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Cornice failures could trigger very large and destructive avalanches.
Problems
Wind Slabs
Lingering wind slabs may still be reactive at higher elevations. Winds have recently shifted directions so wind slabs should be expected on all aspects in exposed terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Some natural deep slab avalanche activity on Saturday has us concerned that the deep weak layer may be becoming a problem in the region. Check out this MIN post for an example of the type of avalanches that might be becoming a problem in the region. The concern is that the mild temperatures and sun may be causing the upper snowpack to settle into a reactive slab above the weak layer at the bottom of the snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices may become weak during the heat of the afternoon. Use extra caution when traveling on ridges and avoid slopes with large cornices overhead during the heat of the afternoon.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 21st, 2023 4:00PM
