Small, isolated pockets of wind slab sitting on a crust have been triggerable by skier traffic recently. Most likely areas to find these pockets are just beneath ridgecrests and roll-overs.
20 cm of snow at upper elevations may sit over a rain crust and/or possibly surface hoar. Human triggering is more likely where the snow had been exposed to wind.
Sunday night: Partly cloudy, light northwest ridgetop wind, freezing level valley bottom.
Monday: Partly cloudy, light northwest wind, alpine high -7, freezing level valley bottom.
Tuesday: Up to 5 cm new snow, moderate to strong southwest wind, alpine high -7, freezing level 500 m.
Wednesday: Partly cloudy, moderate southwest ridgetop wind, alpine high -6 C, freezing level 800 m.
Over the last week, avalanche activity has been limited to size 1 skier triggered storm/wind slabs running on the crust. This great MIN from Friday near Nelson includes a photo of an accidental wind slab.
Please submit your observations to the Mountain Information Network (MIN). Photos are especially helpful! Thank you so much for all the great MINs submitted so far!
Wednesday's storm deposited 6-20 cm of snow. At low to mid elevations early in the storm, light rain is reported to have destroyed some surface hoar and in most places left a freezing rain crust in its place before things cooled and covered it with the remaining storm snow.
There is less known about upper elevations where the new snow may have been more wind affected and sit on a variety of surfaces such as crusts, surface hoar and old wind polished snow. If you have found buried surface hoar from December 8th, we would love to hear about it in the Mountain Information Network.
The early November crust is sitting about 10-30 cm up from the ground. There is a late November crust in the midpack in some places as well. Uncertainty with these crusts exist due to limited observations, but there haven't been any recent avalanches reported on these layers in this region.
Snowpack depths vary with elevation, treeline averages between 50-100 cm.
