snow bridge

A common feature in glacial landscapes—for travelers sometimes a blessing and sometimes a hazard—a snow bridge spans a crevasse in a glacier. Snow bridges form first as cornices, arms of wind-sculpted snow that reach out to each other, like the branches of trees reaching high across a street, sidewalk, or forest path. Eventually the cornices meet and become covered with snow to form a bridge. Robert Falcon Scott, making his way across Antarctica’s Ross Ice Shelf toward the South Pole, like many other polar explorers, suffered losses—dogs, equipment, men—due to collapsed snow bridges: “Suddenly Wilson shouted ‘Hold onto the sledge,’ and I saw him slip a leg into a crevasse. . . . We had been actually traveling along the bridge [over] a crevasse, the sledge had stopped on it, whilst the dogs hung in their traces in the abyss. . . . Why the sledge and ourselves didn’t follow the dogs we shall never know.”

Gretchen Legler