LOS ANGELES (AP) — Emergency crews are scrambling to shuttle food and medicine to residents of California mountain communities stranded by back-to-back winter storms. In San Bernardino County east of Los Angeles, plowing is underway around the clock but authorities say it could take more than a week to reach some areas. In one mountain town, a grocery store roof collapsed Wednesday as safety inspectors were checking on reported damage. No one was injured. The storm could bring heavy snow to the Southwest and some portions of the High Plains, even as record high temperatures hit the Gulf Coast into the Ohio Valley.