Snow fell in Sierra Nevada on the last day of summer, giving the towering mountain range shared by California and Nevada a wintry look in September and making travel hazardous. Mammoth Lakes got more than a dusting Thursday in the first snowfall of the season, with 3 inches reported in the village. Snow coated the roads so heavily that the plows were out, and locals left footprints on sidewalks. Sixteen vehicles crashed on Interstate 80 as snow and hail fell Thursday, killing a man driving a pickup and causing minor injuries to other people, California Highway Patrol Officer Chris Nave said.