Motorists heading toward the Missouri River on I-635 had to find an alternate route Tuesday morning.An overturned semitruck in Tuesday morning's snow forced the closure of both directions of I-635 at Horizon Parkway. Kansas City Scout and MoDOT Kansas City reported heavy traffic backups in the area, and traffic was diverted to southbound I-635 at 69 Highway. The wreck involved a semitruck and a passenger car. Riverside police a man was killed.Authorities said Dwan Brooks, 32, of Kansas City Kansas, was heading south on I-635 on the Missouri River Bridge when the vehicle Brooks was driving was struck head on by the tractor-trailer. The crash remains under investigation.