US | Hurricane Isaac Mississippi Dam About to Fail Residents near Tangipahoa River given 90 minutes to evacuate By Kate Seamons Posted Aug 30, 2012 11:07 AM CDT Copied A motorist navigates through a flooded street, Wednesday, Aug. 29, 2012, in Gulfport, Miss. (AP Photo/John Bazemore) Isaac has not yet dealt his final blow: The Times-Picayune reports that Mississippi's Percy Quin Dam is about to fail as a result of flooding from the hurricane. A mandatory evacuation order was issued for communities along the Tangipahoa River; WWLTV reports that as many as 60,000 will need to exit. The Tangipahoa Parish president says water could reach the area by 11:40am local time. The National Guard is monitoring the dam via helicopter. Read These Next For these factory workers, an unexpected windfall. A request to turn off football game ends in a murder-suicide. JonBenet Ramsey's dad hasn't given up hope in case just yet. Edited version of It's a Wonderful Life has viewers perplexed. Report an error