For example, when travelling over glaciers, crevasses pose a grave danger to a climber who is not roped in. These giant cracks in the ice are not always visible as snow can be blown and freeze over the top to make a snowbridge. At times snowbridges can be as thin as a few inches, and may collapse from people walking over them. Should a climber fall, being protected by a rope greatly reduces the risk of injury or death. The other members of the rope team may proceed with a crevasse rescue to pull the fallen climber from the crevasse.