A snowmobile, also known as a snowmachine, motor sled, motor sledge, skimobile, or snow scooter, is a motorized vehicle designed for winter travel and recreation on snow. It is designed to be operated on snow and ice and does not require a road or trail, but most are driven on open terrain or trails. Snowmobiling is a sport that many people have taken on as a serious hobby. Common brand names in the United States include Arctic Cat, Polaris Inc. and Ski-Doo.

Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout its life cycle, starting when, under suitable conditions, the ice crystals form in the atmosphere, increase to millimeter size, precipitate and accumulate on surfaces, then metamorphose in place, and ultimately melt, slide or sublimate away.