Washington Post: Nestled in the San Juan Mountains at 9,300 feet, and surrounded by 13,000-foot peaks, Silverton, Colo., seems an unlikely place for a dust storm, especially with two feet of snow on the ground. So Chris Landry was alarmed on the afternoon of April 3 when he spotted a brown haze on the horizon; an hour later, a howling wind had engulfed the town in a full-fledged dust storm, turning everything from the sky to the snow a rusty red. “It was almost surreal,” recalled Landry, executive …