Over the last year and a half, the Western U.S. has suffered a rash of devastating landslides. The streak began in September 2013, when heavy rains triggered widespread debris flows across the Colorado Front Range. Then came the tragic landslide that buried Oso, Wash., killing 43 people. Two months later, the West Salt Creek slide, a behemoth rock avalanche in western Colorado, killed three people as it barreled down a 5-kilometer-long path.