Found this educational site and thought I would share it with the forum since there seemed to be some interest in a previous thread.
As an aside, I know the Hyak ski patrol had to rescue a 10 year old boy from a tree well on Saturday. I hear that he was stuck for 10-15 minutes before they dug him out. Thankfully, he was in feet first or it might have been very hard to find him. Not sure how he ended up in that way, but he wasn't able to get himself out. The boy had been skiing with family but they lost track of each other when he went in.
Also, some other skiers pulled another ~12 year old boy from a tree well on Chickamin. While his friend was there with him, he was in the wrong spot to get him out quickly. Some other folks jumped in and pulled the kid out.
look down a few threads. Already covered.