Snow skis

A snow sliding device such as a ski, a monoski, or a snowboard, has a plane of general symmetry P. It includes a principal part, called a body or base 2, which has a longitudinal rib 11 formed between two lateral channels 5a, 5b which open laterally toward the exterior EX and upward HA, and which do not open downward BA. A thin, lower lateral edge 20 extends below the channel. In each of the channels 5a, 5b, a complementary lateral element 3a, 3b, respectively, is attached. A height H of the ski, which corresponds to a distance between an upper surface 30 of the complementary lateral elements 3a, 3b and a lower sliding surface 6, is variable.