Freezing rain and snow from Winter Storm Fisher has caused hundreds of accidents in the Southwest and Southern Plains, including a 21-vehicle pileup in Oklahoma and crashes that killed two in New Mexico. State transportation officials urged Oklahoma residents to refrain from driving Thursday morning because of the dangerous road conditions. Schools are closed in many Oklahoma cities. Winter Storm Fisher will continue to bring a mess of snow, sleet and freezing rain to the region through Thursday night before heading into the South with mostly rain.