South Carolina Governor Nikki Haley said that such heavy downpours were expected to occur only once in 1,000 years, calling it "historic rainfall like we've never seen before."

The tropical air mass that has soaked the southeastern state since Thursday dumped 14 inches (36 centimeters) of rain over the weekend, a new record, according to the US National Weather Service.

"If you are in your house, stay in your house…This is not something to be out taking pictures of," Haley warned.

Nine people died in South Carolina because of bad weather, four of them in traffic accidents.

Some 26,000 South Carolinians did not have electricity and 40,000 had no drinking water, Haley told reporters on the outskirts of the capital Columbia, which has been especially hard hit by the torrential rains.

Emergency measures in place

Officials urged residents not to travel on unsafe roads and imposed curfews in eight cities including the capital, Columbia, where the Congaree River rose three meters (10 feet) in 12 hours, local officials told reporters.

Overnight rains also flooded highways along the coast between Charleston and Georgetown, according to the National Weather Service. Georgetown, which has a population of around 9,000, was mostly under water.

Four major highways leading to it were closed. "We have every ambulance in the county out responding to calls. People are being moved from their homes in boats," Georgetown County spokeswoman Jackie Broach said.

County officials posted links to the official travel advisory online:

Eight water rescue teams from South Carolina were operating and more help was expected from neighboring states, emergency officials said. President Barack Obama also declared a state of emergency in South Carolina on Saturday, making more funds available for the ravaged region.

The southeastern part of the US is experiencing rain in the wake of Hurricane Joaquin, which was around 1,000 kilometers away from the US East Coast on Sunday. Joaquin damaged houses and uprooted trees in the Bahamas last week.

mg/msh (dpa, Reuters, AFP)