A snowmobile is a land vehicle propelled by track at the rear and ski(s) up front for steering. Early snowmobiles used rubber tracks, however a modern snowmobile will have a track made of a kevlar composite. They are designed to be operated on snow and ice, and require no road or trail. Most snowmobiles are typically powered by two-stroke gasoline/petrol internal combustion engines. Four-stroke engines are becoming more and more popular in snowmobiles. Summertime occupations for snowmobile enthusiasts can also involve drag racing on grass, asphalt strips, or even across water. People who ride them commonly are known as snowmobilers. The three main types of riding are Snowcross/racing, trail riding and mountain climbing.
Grass drags are held every summer to fall (autumn), with the largest event being Hay Days in Lino Lakes, Minnesota. Hay Days has always been the first weekend following the Labor Day Holiday.