Sentence:  Townsend hare inhabit this area, particularly above the cabin, and a skier is likely to have one explode from a <WSD>tree well</WSD> and disappear into the whiteness as he skis by. Life is a constant bivouac for them -- they spend days huddled in <WSD>tree wells</WSD> during storms -- but I suspect they are as content and warm in their luxurious coats as we are in a cabin. 
Meaning of the word marked with <WSD> tags:  A hole or depression in the snow around the base of a tree caused by the tree's canopy preventing the accumulation of snow.