Snow sculpture, snow carving or snow art is a sculpture form comparable to sand sculpture or ice sculpture in that most of it is now practiced outdoors often in full view of spectators, thus giving it kinship to performance art. The materials and the tools differ widely, but often include hand tools such as shovels, pickle forks, homemade tools, and saws. Snow sculptures are usually carved out of a single block of snow about 6–15 ft (1.8–4.6 m) on each side and weighing about 20–30 tons. The snow is densely packed into a form after having been produced by artificial means or collected from the ground after a snowfall.