US / Hurricane Isaac Mississippi Dam About to Fail Residents near Tangipahoa River given 90 minutes to evacuate By Kate Seamons, Newser Staff 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. (More Hurricane Isaac stories.) Report an error