Members of the Vicksburg Fire Department and county crews head out on a boat, past a partially submerged building, as they prepare to sandbag areas on the levee to slow down floodwater from the swollen Mississippi River in Vicksburg, Mississippi May 11. Heavy flooding in the U.S. Midwest shut Ohio River terminals, limited barge movements and threatened to disrupt refinery operations along the Mississippi River to the Gulf of Mexico on Wednesday.