The deep hole that surrounds the base of a tree under its boughs after heavy snowfalls. During heavy winter snow storms, the boughs keep snow from accumulating near the base of the tree creating a "well" around the tree which can become, in the mountains, very deep. Out of bounds skiers and snow boarders have died from suffocation or hypothermia after falling into tree wells.
A 36 year old skier died of suffocation on Mt. Baker last week after falling into a tree well.