Local officials in Southern Mississippi have ordered a mass evacuation after heavy rainfall from Tropical Storm Isaac is threatening a dam in Tangipahoa Parish.

Mississippi officials warned Gohsep and Tangipahoa parish government of an "imminent failure" of the dam at Lake Tangipahoa at Percy Quinn state park, which is expected to cause additional flooding along the already swollen Tangipahoa river, Yahoo news reports.

According to WWLTV, up to to 60,000 people will need to evacuate along the Tangipahoa River and they have about 90 minutes to get out before the water would get too high to do so safely.

Residents can go to shelters set up at schools.

The Enterprise-Journal in McComb reported in June that Lake Tangipahoa was set to be drained in order to "rework the dam and spillway valve." According to the paper, the work was expected to take all winter.

Isaac claimed one life in Mississippi after a male tow truck driver was killed on the job by a tree that fell around midnight, Pearl River Emergency Management Deputy Director Amanda Harris told ABC News. The man's name and age has not yet been released.

President Obama declared federal emergencies in Louisiana and Mississippi late Wednesday, according to a statement from the White House. The disaster declarations free up federal aid for affected areas.

Of Louisiana's 64 parishes, 58 are under states of emergency this morning.

According to the National Hurricane Center, Isaac is slowly weakening over Central Louisiana, but still producing heavy rains, severe weather and high water levels along the Northern Gulf Coast.