Workers clean up a manhole in a flooded street as Tropical Storm Debby moves across Georgia, in Savannah, Georgia, U.S., on August 6, 2024. / REUTERS/Marco Bello

ATLANTA (Reuters) - Tropical Storm Debby inundated coastal Georgia and South Carolina with a deluge of rain that could bring "catastrophic flooding" to Charleston, Savannah, and other cities on Aug.6, a day after it slammed into Florida's Gulf Coast as a hurricane.

At least six people have died in Florida and Georgia in the wake of the storm, which is expected to linger over the southeastern and mid-Atlantic coasts for days.

"Debby is expected to produce potentially historic rainfall. Totals of 10 to 20 inches (25 cm and 51 cm), with maximum amounts of 25 inches (63.5 cm), bringing areas of catastrophic flooding across portions of the eastern half of South Carolina, and southeast North Carolina through Friday," the National Hurricane Center said.

The governors of those states have declared states of emergency.

The storm featured 40-mile-per-hour (64 kph) winds as it moved slowly just south of Savannah, Georgia, on Aug. 6 afternoon. Heavy rainfall could cause flooding in parts of the mid-Atlantic through Sunday, the Miami-based center said.

More than 8 inches (20 cm) of rain have already fallen on Savannah and Valdosta, Georgia, the National Weather Service said. Charleston and Hilton Head, South Carolina, have received between 10 and 12 inches (25 and 30 cm) of rain so far, the weather service said, with more on the way.

In Savannah, rain was coming down hard outside the landmark Bellwether House, a 16-room bed-and-breakfast in the city's historic district, but general manager Victoria Hill was not too concerned.

"This place was built in 1876," she said. "It's built rock-solid, and you can imagine how many storms have hit over the last century."

Hill said many tourists had canceled their reservations because of the storm, but a handful of guests were staying on.

"We here, we're open and we're holding up. We'll all ride this out together."

Charleston Mayor William Cogswell said more than 2 feet (61 cm) of rain was expected in his city before the storm passed. Even at low tide, storm surges of between 4 and 6 feet (1.2 and 1.8 meters) will prevent floodwaters from draining into the sea, he said.

There are "not enough pumps in the world" to handle that much rain, Cogswell said late on Aug.5. He has since extended a citywide curfew until Aug. 7 morning.

"Nobody should be out on the streets in these conditions unless it is an absolute emergency," the mayor said.

About 50 miles (80 km) west of Charleston, fears of a breach at the McGrady Dam in Colleton County, part of the state's Lowcountry, prompted the county sheriff's office to warn residents to evacuate immediately on Tuesday morning.

Debby made landfall as a Category 1 hurricane in the Big Bend region of Florida's Gulf Coast on Aug.5 morning, dumping 8 to 16 inches (20 to 41 cm) of rain in parts of central Florida, according to local reports. The storm has been blamed for five deaths in Florida and one near Valdosta, Georgia.

More than 88,000 customers were without power in Florida as of Tuesday afternoon, according to poweroutage.us, down from a peak of 350,000 on Monday. And more than 10,000 were without power in Georgia. Hundreds of flights to and from the state were canceled.

Weather conditions could spawn tornadoes as well, according to the National Hurricane Center (NHC). A suspected twister flipped over cars and damaged restaurants in Moncks Corner, South Carolina, about 30 miles (48 km) north of Charleston, early on Tuesday morning. Mayor Thomas Hamilton said there were minor injuries.

The NHC said Debby would slow down and move east and off Georgia's shore on Tuesday before turning north and drifting inland over South Carolina near Charleston on Aug.8.

Vice President Kamala Harris postponed a presidential campaign stop scheduled this week in Savannah, the Savannah Morning News reported.

Savannah Mayor Van Johnson said the city could expect a "once-in-a-thousand-year" rain event.

"This will literally create islands in the city," Johnson said.

Cedrick King, a businessman from coastal Brunswick, Georgia, said he and his family had packed up their belongings on Tuesday and were ready to make the five-hour drive to Atlanta.

"We're headed north, far away from this storm," he said.