At least two tornadoes hit Oklahoma Tuesday, killing at least four people. (The Associated Press first reported seven deaths.) The storms struck during rush hour, injuring motorists along Interstate 40 and U.S. Route 81, Canadian County Sheriff Randall Edwards said, while destroying houses and causing a gas leak in the nearby city of El Reno. Officials said the storm system was moving north toward Oklahoma City. More twisters are also expected to hit Joplin, Missouri, the city devastated Sunday by a tornado that claimed at least 122 lives, the single-deadliest tornado since records started being kept in 1950.