Isaac claimed its first American life on Thursday after a tow truck driver was killed clearing debris from the storm in Mississippi. Isaac was downgraded to a tropical storm on Thursday, but the slow-moving storm refused to let up on the Louisiana coast as flooding trapped residents in their homes and on levees. Worst affected is Plaquemines Parish, outside New Orleans, where National Guardsmen and residents rescued dozens who were trapped in their homes after a levee overtopped. Louisiana Gov. Bobby Jindal warned there is “much more coming” as the rain and the winds are expected to last through Friday and upwards of 300,000 are still without power in the Southeast.