Crevasse is a large, deep fissure; especially, in a glacier: “The exploration team moved carefully over the glacier, watching for any existing dangerous crevasse.”
Crevice is a narrow split or crack: “It always amazes me that flowers in the desert grow within almost any crevice in rocks.”
The determined tree grew from the crevice of the rocks on the side of the mountain; however, further up there was a glacier and nothing could grow in its crevasse.
