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.
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.
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.
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.
A group of skiers triggered a size 2.5 in the West Bowl at the Lake Louise ski area today (which has been closed all season). This was 550m long, 200m wide, and 40- 50cm deep. This avalanche failed on the ground and cleared all snow off of the slope until it came to rest at the deposit. One skier was almost completely buried while a second was fully buried and did not survive.
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.
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.
