NEW : Officials say high temperatures will make travel dangerous for drivers . A weather report shows images of overturned vehicles and collapsed carports . The storms could be among the world 's very worst since record - keeping began in the 1940s . Officials warn of treacherous road conditions .
NEW : Officials say falling temperatures will make roads dangerous for drivers . A CNN affiliate shows images of overturned vehicles and collapsed carports . The storms could be among the area 's 10 worst since record-keeping began in the 1940s . Officials warn of treacherous travel conditions .