A ski is a long, flat device that is worn on the foot and is designed to help the wearer slide smoothly over snow. Originally it was intended as an aid to travel in snowy regions, but they are now mainly used for recreational and sporting purposes. Also, a ski may denote a similar device used for purposes other than skiing, for example, for steering snowmobiles. Skis were usually wooden planks made from a single piece of wood, however, now they are made from a complex assembly of components including glass fiber, Kevlar, aluminum etc. Most skis are long and thin and curve upwards at the front to prevent digging into the snow. Snowboards on the other hand are boards, usually with a width the length of one's foot, with the ability to glide on snow. In Portland skiing and snowboarding are a popular sport. Ski and snowboard dealers in Portland are listed with YellowPagesGoesGreen.