After a few stunning days without the west winds, they returned Sunday afternoon and should usher in cloud and a touch of snow for Monday. With diminished solar input the sensitivity of the persistent slab should diminish but keep it in mind...
This crust facet layer down 20 to 40cm on steep slopes at treeline and above has produced several natural and skier triggered avalanches over the last few days. Diminishing solar inputs and cooling should decrease the sensitivity of these slabs.
A low pressure system is set to sweep down through Alberta from the NW Sunday night.. this will bring increased clouds in the morning and light snow in the afternoon. Freezing levels should just reach valley bottom and the clouds should keep solar heating at bay however expect westerly winds to continue to build into Monday morning.
20-40 cm of snow has solidified into a slab overlying the February 16 sun crust on steep southerly aspects. Solar heating has created new crusts on steep solar slopes. Westerly winds returned Sunday to create light wind effect on alpine slopes.
Forecasters in the Chickadee and Boom valleys today saw evidence of slab activity on steep solar slopes: a sz 2.5 Na likely initiated Saturday right at treeline and may have reached Boom Lake while a sz 2 moist slab initiated with solar heating in one of the Chickadee paths just below the rocks at treeline to wipe out several sets of tracks...
