Extreme skiing is performed on long, steep (typically from 45 to 60+ degrees, or grades of 100 to 170 percent) slopes in mountainous terrain. The French coined the term 'Le Ski Extreme' in the 1970s. The first practitioners include Swiss skier Sylvain Saudan, who invented the windshield wiper turn in the mid-1960s, and in 1967 made the first descents of slopes in the Swiss, French and Italian Alps that were previously considered impossible. Saudan's 'first descent' in America was at Mt. Hood March 3, 1971. Early American practitioners include Bill Briggs, who descended Grand Teton on June 16, 1971. The Frenchmen Patrick Vallençant, Jean-Marc Boivin and and the Italians and were among those who further developed the art and brought notoriety to the sport in the 1970s and 1980s.