The Gunnison River drops an average 43 feet per mile through the canyon, making it one of the steepest mountain descents in North America. Black Canyon is aptly named: its steepness makes it difficult for sunlight to penetrate down the canyon. Canyon walls are often shadowed and therefore appear black. The area is a center for traditional climbing — a difficult style of rock climbing practiced only by advanced climbers. Rafting is available as well, but is also difficult and is similarly attempted only by the most advanced kayakers.