New snow and wind have created sensitive wind slabs, especially at upper elevations. Skier triggering is likely. Conservative terrain selection is advised.
This problem includes fresh surface wind slabs, and previously formed wind slabs that are now hidden. The surface wind slabs are likely to be easily human triggered in lee and cross-loaded features.
Thin areas are locations where it is more likely to trigger this weakness.
Observations were limited today in poor visibility, but forecasters on Monday were triggering smaller pockets of the fresh wind slab up to size 1. Natural avalanche activity was also observed up to size 1.5 on steeper east aspects. Given the additional snow and continued wind, it is likely that more avalanche activity is ongoing.
Another 10 to 20cm of new snow in the past 24hrs brings the 72hr total to 30-40cm. This recent snow has created 30-50cm deep fresh wind slabs due to very strong westerly winds. These slabs sit on a weak layer of surface hoar, graupel, and/or stellars, and has been reactive to ski cutting and natural avalanche activity. In addition, previously formed wind slabs (now buried) are widespread in the Alpine and open areas at Treeline. These buried slabs may now be less sensitive to triggering, but it is worth digging down and checking it out. The November crust still lingers at the base of the snowpack down 170cm or so and is still a concern for triggering from thinner snowpack areas.
Wednesday looks to be cloudy with a high of -12C. Winds will continue in the 80+km/h range out of the West at ridgetop. Another 10cmof new snow is expected by end of day.
https://hpfx.collab.science.gc.ca/~fsg006/productviewer/ab/table/AB_Rockies_Forecast.html
More details can be found in the Mountain Weather Forecast.
