Something different for your reading pleasure today. Having formerly skied a lot in the Pacific Northwest, I've had a few encounters with tree wells from hell. Little did I know there was an entire web site devoted to the topic.
A tree well is an area around the base of a tree where the snow is poorly consolidated. A fall into one of these wells can be extremely treacherous, especially if you are alone, as it is very difficult to extract yourself without the help of a partner. A head first fall into a tree well can result in death from suffocation. This sounds like an urban myth, but it is not.
Have a look at the Tree Well and Deep Snow Safety web site for more information.