A blinding dust storm rolled across the Arizona desert Tuesday, causing three pileups involving dozens of vehicles on a major interstate. A 70-year-old man was killed and at least 15 other people were injured, authorities said. The first two crashes occurred just after noon as a dust storm suddenly covered Interstate 10 near Picacho, about midway between Phoenix and Tucson. Those collisions involved 16 vehicles and led to the fatality. Video showed dust roiling over dozens of cars, tractor-trailers and ambulances pulled over or strewn about the highway.