Lots of great info, thanks everyone. I guess one big thing will be that if I fall and am sliding in a treed area, spin around as quick as possible so I am sliding feet first. And of course try to avoid treewells in the first place.
If someone finds themself headfirst in a treewell, skiing alone with no one to rescue them, what's the best method at attempting to free yourself? Try to create an airhole with your hand and use Avalung if available, of course, but after all that, when it's actually time to try to get out. Just try to struggle out and use raw strength, or is there technique to it? What angle to go at, use just arms or just legs or both, etc. Cirquerider, maybe you could elaborate on what you meant? "If all else fails, and you don't have a buddy to bail you out, your only shot is to release your skis and get upright." Are you referring to while it's happening, or after being submerged and coming to a standstill?
@carvemeister, I already have a small ski pack without Avalung that I got for inbounds skiing. At the time treewells didn't even cross my mind; I saw Avalung as avalanche protection and nothing more, and due to avalanche control inbounds, didn't see a need for one inbounds. (Of course avalanches CAN happen inbounds, but it's really rare.) My plan was (and still is) to get a bigger pack with Avalung, along with other backcountry gear (beacon/transponder/shovel/probe) when I move to the mountains.
Thanks for posting the video, that place looks like a lot of fun.
Try to create an air pocket. Get this part of it straight though... you WON'T get yourself out if you're upside down. Hope someone saw you or finds you. Otherwise, enjoy the flashbacks and make your peace. You'll either suffocate or freeze to death.