At least six people were killed and dozens injured by a strong storm that swept through the Southeast yesterday. Suspected tornadoes were reported in Louisiana, Mississippi, Alabama, and South Carolina. In South Carolina, three people were killed and five injured, and in northern Georgia, a man was killed when a tree fell on his car. Dozens of homes were damaged, and thousands were left without power after the storm. York County, S.C., has requested state assistance in cleaning up the damage.