The governor in South Carolina says at least six reported deaths as a result of the floodings rains in areas have been higher than at any given moment in 1,000 years.
More than 35cm (13 inches) has dropped in three days in Charleston’s historic city.
Schools will remain close on Monday and several inter-state highways are closed.
The thunderstorm isn’t anticipated to strike at the eastern US, but the wetness connected with it’s leading to significant rain.
“We haven’t found this amount of rain in the low state in 1,000 years.
Ms Haley encouraged residents to stay indoors.
“The water isn’t safe and lots of places around the state in which you see this deep water, it is got bacteria inside. Thus, stay inside and do not get in there,” she said.
The move means local and state authorities can receive federal help manage the flood.
“State and local authorities have every ambulance in the county out reacting to calls.
About 100 people were saved from their automobiles on flooded roads on Saturday.
In Charleston’s historical city centre, many roads are shut and sandbags are piled as much as keep floodwaters outside.