A submerged tractor sits in front of a home after Hurricane Isaac along Highway 23 in Ironton, Louisiana Aug 30, 2012. Hurricane Isaac forced evacuations affecting tens of thousands of people in Louisiana and Mississippi on Thursday, even as relieved New Orleans residents said its destruction was nothing like that seen after Hurricane Katrina in 2005. [Photo/Agencies]

Residents of Mandeville walk through a flooded street as Hurricane Isaac passes through Mandeville, Louisiana, Aug 30, 2012. [Photo/Agencies]