Isaac was downgraded to a tropical depression on Thursday and is moving into the central United States.
It left little damage in New Orleans, where stronger barriers were installed after Hurricane Katrina in 2005 but leaving large areas of the region flooded.
A report says that seven tornadoes have spun off from Isaac in Mississippi and Alabama.
A tornado that touched down in Gulfport, Mississippi had caused significant destruction to homes.
Now, there is a potential failure of Lake Tangipahoa Dam in Mississippi’s Percy Quin State Park.
Authorities ordered the immediate evacuation of tens of thousands of residents in nearby communities in Louisiana and Mississippi as a protective measure if the dam burst flooded the areas.