By Harriet McLeod and Scott Malone
CHARLESTON, S.C./SAVANNAH, Ga. (Reuters) - Hurricane Matthew slammed into South Carolina on Saturday, packing a diminished yet still potent punch after killing almost 900 people in Haiti and causing major flooding and widespread power outages as it skirted Florida and Georgia.
Now weakened, the most powerful Atlantic storm since 2007 unleashed torrential rains and damaging winds in Florida before churning slowly north to soak coastal Georgia and the Carolinas. Wind speeds at midday had subsided by nearly half from their peak about a week ago to 75 miles per hour (120 kph), reducing the storm to a Category 1 hurricane, the weakest on the Saffir-Simpson scale of 1 to 5.
Matthew, which topped out as a ferocious Category 5 storm days before, made U.S. landfall near McClellanville, South Carolina, a village 30 miles (48 km) north of Charleston that was devastated by a Category 4 hurricane in 1989.
The National Hurricane Center in Miami said Matthew passed over Myrtle Beach, South Carolina, on Saturday afternoon, and warned of potentially life-threatening flooding in Georgia and North Carolina even as the storm slowed as it plowed inland.
As of 11 p.m. EST (0300 GMT), the storm was about 35 miles (55 km) south of Cape Lookout, North Carolina, the center said in an advisory.
The center of the storm will move near or south of the North Carolina coast early on Sunday and east of the state later in the day as it weakens.
The storm was blamed for at least 11 deaths in the United States - five in Florida, three in North Carolina and three in Georgia, including two people killed by falling trees in Bulloch County, the county coroner said.
Power was reported knocked out to more than 2 million households and businesses in the U.S. Southeast, the bulk of those in Florida and South Carolina.
North Carolina Governor Pat McCrory urged residents on Saturday evening to stay off roads and sidewalks to avoid "deadly conditions" caused by severe flooding and debris.
Conditions in eastern and central North Carolina were expected to worsen as the storm edged along the coast and toward the Outer Banks barrier islands, the governor said.
Forecasters warned that widespread flooding was possible from heavy rain - 15 inches (40 cm) was expected to fall in some areas - along with massive storm surges and high tides.
The storm-stricken stretch of the Atlantic Coast from Miami to Charleston, a nearly 600-mile drive, encompasses some of the most well-known beaches, resorts and historical towns in the southeastern United States. Parts of Interstate 95, the main north-south thoroughfare on the East Coast, were closed due to flooding and fallen trees, state officials said.
Roads in Jackson Beach, Florida, were littered with debris, including chunks from an historic pier dislodged by the storm, with some intersections clogged by up to a foot of standing water. Beachfront businesses suffered moderate damage.
"We rode out the storm. It wasn't this bad at our house, but here there's a lot of damage," said Zowi Cuartas, 18, as he watched bystanders pick up shattered signs near the beach.
Florida Governor Rick Scott said more than 6,000 people stayed in shelters overnight, but he appeared relieved that the state had been spared from greater harm.
"We're all blessed that Matthew stayed off our coast," he said. He predicted electricity would be restored to most homes by Sunday evening.
Streets in downtown Charleston, known for its historic waterfront architecture, were flooded to the tops of tires on some parked cars, and a few residents could be seen wading near the city's sea wall as high tide approached.
Tony Williams, 54, who said he is homeless, rode his bicycle against huge wind gusts after spending the night in a public garage. "I just got tired of laying where I was laying," he said.
On Daufuskie Island near the Georgia border, writer Roger Pinckney, 70, said it "blew like hell" as he hunkered down at home despite evacuation warnings during the height of the storm's fury, but he emerged unscathed.
Some 8 inches (20 cm) of rain fell in the Savannah, Georgia area, downing trees and causing flooding.
The National Weather Service said record-high tides were recorded along the Savannah River at the South Carolina-Georgia border, peaking at 12.6 feet, surpassing those from Hurricane David in 1979.
Though gradually weakening, Matthew was forecast to remain a hurricane until at least Sunday, when it was expected to creep away from shore, the NHC said.
DEATH TOLL ROSE IN HAITI
Storm damage was far greater in Haiti, where at least 877 people died earlier when the storm plowed directly into the impoverished Caribbean island nation.
Matthew howled through Haiti's western peninsula on Tuesday with 145 mph (233 kph) winds and torrential rain. Some 61,500 people were in shelters, officials said, after the storm lashed coastal villages in high surf.
The U.S. military began sending aid to Haiti by air and sea, including a Navy amphibious transport ship carrying heavy-lift helicopters, bulldozers, fresh-water delivery vehicles and two mobile surgical units.
The Haitian government warned that a deadly outbreak of cholera could worsen, confirming dozens of new cases of the water-borne disease since the storm hit, 13 of them fatal.
Officials in Florida, grappling with an outbreak of Zika, said they hoped the flooding would not worsen the spread of the mosquito-borne virus, which can cause fever and birth deformities.
"We have got to get rid of standing water as quickly as we can," Governor Scott told reporters.
(Additional reporting by Brendan O'Brien in Milwaukee, David Bailey in Minneapolis, Zachary Goelman in Orlando, Fla., David Shepardson in Washington, and Steve Gorman and Lisa Richwine in Los Angeles; Editing by Bernard Orr and Stephen Coates)