The girl disappeared Sunday evening in Yazoo City. Her mother said a flash flood swept the child into a drain under a road.
Joey Ward, the Yazoo County director of emergency management, said up to 5 inches of rain had fallen in the area.
Some parts of the south got even more rain with more than 7 inches reported in Vestavia Hills in the Birmingham, Ala., area. A hotel in the Birmingham suburb of Homewood was evacuated.
Flooding was also reported or predicted in Georgia and Florida.
The Mississippi Emergency Management Agency said at least seven people received minor injuries and some damage was done to buildings by a suspected tornado in Covington County. The apparent touch-down occurred at about 2 a.m. Monday.
Ward said ditches around the missing girl's house were searched by divers Sunday night. On Monday, he said there was little hope of finding the girl alive and the search was now for her body.
“You move to recovery when all rescue efforts have been exhausted, as well as the time the person could reasonably stay alive given the conditions,” he said.
Road conditions were so bad in the area after the storm that schools in Yazoo County closed Monday.