CHARLESTON (South Carolina) • Pounded by heavy rain and an unusually high tide, the historic port city was paralysed by flash floods, its elegant streets transformed into coursing riverways.

Officials sealed off the low-lying peninsula in the heart of the city for much of the day, declaring it "substantially underwater in various parts" last Saturday, although it seemed that the floodwaters caused more inconvenience than tragedy in the city of 130,000.

About 60 streets in the city were closed, many businesses were closed, and numerous fairs and festivals were cancelled.

But Mayor Joseph Riley Jr said only a handful of residents called to report water in their homes.

"We don't anticipate... any substantial property damage," Mr Riley said in an interview last Saturday night, adding that the city was bracing for more rain.

Mr Pete Mohlin, a National Weather Service meteorologist, said that up to 20cm to 25cm more could fall in the area over the weekend. A flash-flood watch was in place for Charleston, Berkeley and Dorchester counties, he said.

The record rainfall in Charleston was the result of a low-pressure system that lumbered through the Carolinas and eastern Georgia, sucking in moisture from Hurricane Joaquin, the Category 4 storm that spun east over the Atlantic last Saturday, hundreds of kilometres south-west of Bermuda.Joaquin was expected to pass west of Bermuda yesterday, the National Hurricane Centre said, while forecasters also posted a hurricane watch.

Last Saturday afternoon, the White House said President Barack Obama had declared an emergency in South Carolina.

Mr Obama ordered "federal aid to supplement state and local response efforts".Emergency declarations were also in effect in parts of Delaware, Maryland, New Jersey, North Carolina, South Carolina and Virginia.

Weather officials said that some cities in South Carolina had received more than 25cm of rain since last Thursday and that forecasters did not expect the storm to relent until yesterday, at the earliest.

NEW YORK TIMES