MOUNT PLEASANT, S.C. — Tropical Storm Gaston sloshed ashore in South Carolina Sunday with near hurricane-force wind, spinning sheets of rain that flooded roads as the storm knocked out power to thousands of people.

Gaston made landfall near McClellanville, a small fishing village that was walloped by Hurricane Charley earlier this month when it came ashore for a second time after devastating southwest Florida.

Gov. Mark Sanford declared a state of emergency Sunday and encouraged “folks to stay in their homes for the time being so that damage assessment crews, utility truck crews and debris removal crews can do their jobs.”

As much as eight inches of rain had fallen along some parts of the coast by midday, and a flash flood watch was in effect. Hundreds of residents were urged to evacuate ahead of the storm.

Hours after the eye of Gaston came ashore, steady sheets of rain pelted Mount Pleasant. Tree limbs littered flooded roadways, some of which were impassable. Palmettos were pushed to the pavement and road signs twisted in the wind.

Across the harbor in Charleston, Gaston flooded streets and pushed over power poles. At least 125,000 people were without power at the height of the storm.

The rain tapered off along the coast by midday, but blustery wind still raked the coastline near Charleston and intersections throughout the area had no traffic lights.

“The important thing is that we don’t have any false sense of safety that it’s all over,” said Charleston’s mayor, Joseph P. Riley Jr. “We have downed trees and often times there are power lines under those downed trees.”

By midday, Gaston was moving north about 8 mph toward inland South Carolina, weakening along the way but still prompting flood watches and warnings of wind gusts as high as 60 mph.

Charleston County officials said there was only one initial report of a serious injury — a resident injured when a tree fell on a home.

“It just goes to show that the residents took the proper precautions that they needed to take and shows they were prepared,” said Roland Windham, the Charleston County administrator.

Residents in low-lying areas in Charleston and Georgetown counties were urged to move to higher ground before the storm hit. Authorities also asked people living in mobile homes to evacuate.

“We hope we don’t experience any more injuries during the cleanup,” Windham said. “That’s typically when you see a lot of injuries occur.”

John Legare of the state Emergency Management agency said about 30 people had sought refuge in five shelters in coastal counties as Gaston approached. Shelters were opened in at least one inland county.

Gaston — the hurricane season’s seventh named storm — had maximum sustained winds of 70 mph when it hit land but was down to 45 mph by early afternoon. Forecasters said the weakened storm could reach North Carolina by Sunday night.

Legare said the storm had picked up speed, which could mean less flooding.

“The faster it moves, the less chance it has to rain,” Legare said. “But until it has passed through, I don’t think we can say flooding is not a concern.”

In the Atlantic Ocean, meanwhile, Hurricane Frances had sustained winds of 135 mph about 550 miles east of the Leeward Islands in the southeastern Caribbean.

The National Hurricane Center in Miami said people from Cuba to the southeastern United States should closely monitor the progress of the storm, which could strengthen on Sunday and threaten land by Labor Day weekend.