when I skied Gran Targhee, the staff told us to stay with a buddy. they recovered bodies in the spring... if you went off the trail and hit a tree, the snow fall off the tree would bury you without a trace. that was in the 80’s.. no cell phones then.. and thats what 30-40 feet of snow will get ya!
Yep, “tree wells.” Happens once in a while even inside ski area boundaries. Someone runs into a tree and gets buried, sometimes head-down, in the deep snow surrounding a tree. The worst thing is to be knocked unconscious by the impact and end up upside down under the snow. Many suffocate that way.
It’s amazing how deep snow can be in some places. I used to ski the back bowls at Vail once in a while, and the snow was often so deep that if you didn’t have ankle straps securing your skis, they would just be lost for good if they came off. The brakes that are enough to stop skis on normal runs were useless in that deep powder.