The Mist (2007)

The Draytons - David, Steff and their son Billy - live in a small Maine town. One night a ferocious storm hits the area, damaging their house. The storm is accompanied by a strange mist the following morning. David and Billy and their neighbour Brent Norton go into town and find themselves trapped in a grocery store with several other people. There they discover that the mist contains something frightening and intent on killing humans.