Avalanche Forecast
Issued: Apr 22nd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs, Storm Slabs and Loose Wet.
TH,
Avalanche Canada
Despite the slow down in natural activity, the deep persistent slab problem remains a serious concern for human triggering. Avoiding steep terrain, especially in shallow snowpack areas, is the only way to manage this reality.
A warm up over the next two days may make these slabs more sensitive.
Summary
Confidence
Moderate
Avalanche Summary
A skier-triggered avalanche occurred in a closed area within the Lake Louise ski resort. Two people were caught. One was partially buried and survived. One was fully buried and did not survive. The avalanche was reported to be 200 m wide and 550 m long with a crown depth of 40-50 cm.
Snowpack Summary
Almost daily accumulations of new snow are competing with new sun crust formation on solar aspects with multiple buried crusts present in the upper snowpack. On northerly aspects, up to 40cm of recent snow remains preserved with buried temperature crusts as high 2200m. The basal snowpack remains weak with facets and depth hoar.
Weather Summary
A cold front approaches the region Sunday afternoon. 2-5mm of rain below 2000m with freezing levels rising to 2100- 2400m. Winds will increase to 30 to 40km/hr SW.
Overnight freezing levels only drop to around 1700m with overcast skies as winds will decrease to 20-30km/h. This will lead to less crust recovery than has been seen for several days.
Terrain and Travel Advice
- Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
- Cornice failures could trigger very large and destructive avalanches.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Deep Persistent Slabs
The weak basal facets and mid-pack facets/crusts remain a concern, and will remain so for the foreseeable future. Avoid steep terrain especially in shallow snowpack areas where triggering is more likely.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Storm Slabs
5cm can be expected to fall as snow in the alpine and upper treeline into Monday with SW winds. Pay attention to recent accumulations that overlie crusts. Local slab formation will vary greatly with temperature and wind effects.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
With freezing levels rising and small amounts of rain forecast, expect heating to create moist snow at lower elevations. As this affects snow that has accumulated over crusts it may fail naturally in very steep terrain and with skier traffic in steep terrain.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Apr 23rd, 2023 4:00PM
