Another rise in avalanche danger Weds/Thurs will depend on the storm’s timing and snowfall totals. With the new load arriving soon after the last event, conditions will tip easily. The pump is primed.
Although the storm has passed and Tuesday offered only a brief pause between a pileup of stacked weather systems, ongoing strong winds will continue to produce dry loose conditions. Snow returning Wednesday will once again add more snow to the problem.
A storm ending Tuesday morning has produced storm slabs, now as deep as 60cm. At the same time, wind slabs continue to build in exposed lee terrain. While the storm and cycle has peaked, the remaining slabs remain ripe for human triggering.
Lots of action on Tuesday. Lake Louise reported 28 explosive controlled avalanches today, including five size 2s up to 70 m wide and 50 cm deep. They suspect the deeper slabs were failing on the mid-November crust. Sunshine noted numerous ski cut size 1s along with a few explosive controlled wind slabs to size 1.5. Parks Canada also triggered a size 3 on Mt. Bosworth with Gaz-Ex, producing a 100 cm crown that dusted the highway.
30-60 cm of recent storm snow has formed storm slabs and been blown into wind slabs at treeline and above. These slabs sit on a variety of buried crusts in the snowpack, however few avalanches have been noted on these layers so far. Below treeline snow remains generally soft with a supportive mid-pack.
Model guidance suggests another delivery of substantial precip arriving Wed into Thu. The West side of the forecast area could see up to 40, while the East is closer to 20. The load will be accompanied by strong and sustained W/SW wind. Temps trend warmer, with the valley hovering near 0 and ridge elevations around –6.
The sharpness of the combined weather inputs will send the avalanche danger up very quickly.
