For anyone climbing or ski-touring in the alps or other glaciated mountain ranges, a knowledge of crevasses and crevasse rescue techniques is essential. While kits to make crevasse rescue easier are produced commercially, a simple crevasse rescue kit for self rescue or for rescuing a partner can be made from a long sling, a Prusik loop or a rope clamp of some sort, a pulley and a few karabiners. There is a good article on Crevasse Rescue on the BMC Website.