After a protracted and violent journey up the southeast U.S. seaboard, a weakened Hurricane Matthew made landfall this weekend in South Carolina, inundating a vast stretch of the coast with torrential rain and triggering floods far inland.

As the slow-moving tempest moved northeast, some towns saw as much as four inches of rain per hour. A record 14-plus inches drenched Fayetteville, N.C., where the soil was already saturated from heavy September rainfall. Water rescue teams worked through the night Saturday to save thousands stranded in stalled cars and flooded homes.

By 6 a.m. Sunday, teams had rescued more than 562 people in 218 calls, said Michael Martin, a battalion chief with the Fayetteville Fire Department. “We’re still rescuing people,” Martin said. In the early hours of the storm, most of them were motorists, he said, but as floodwaters rose, teams started evacuating residents trapped in their homes.

Flooding and power outages were reported early on in the Virginia Beach area. Numerous roads in the Tidewater area were closed or impassable.

Matthew knocked out power to more than 1.3 million people and has been blamed for more than a dozen deaths, including at least seven in North Carolina, four in Florida and three in Georgia. In South Carolina, one person died attempting to drive through floodwaters on Saturday, according to the state’s governor, Nikki Haley (R). Meanwhile, in Haiti, slammed by Matthew earlier in the week, the toll continues to rise. A government official put the death count at 470 in one Haitian district, the Associated Press reported.

Residents from Florida to South Carolina survey the damage left behind by Hurricane Matthew. (McKenna Ewen,Whitney Leaming,Lee Powell,Ashleigh Joplin/The Washington Post)

The hurricane had remained just offshore as it passed Florida’s beaches and Georgia’s sea islands on Friday and early Saturday, but its northern eyewall scraped land at Hilton Head Island and Pritchards Island, S.C., with 105 mph winds.

Shortly before daybreak Sunday, the hurricane was downgraded to a post-tropical cyclone, according to the Associated Press. As of 8 a.m. Sunday, the storm was centered about 60 miles southeast of Cape Hatteras, N.C., moving out to sea. It still had hurricane-force winds of 75 mph.

Hurricanes have many tools of destruction, from wind to storm surge to rainfall, and these latter two elements may be Matthew’s most dangerous features at this point. Rainfall totals in Savannah, Ga., topped 17 inches. Trees in the utterly soaked ground toppled across the region.

Officials in North Carolina had feared a repeat of Hurricane Floyd, the 1999 storm that had a similar track to Matthew’s — teasing Florida’s east coast before heading to the Carolinas — and that dropped catastrophic quantities of rain. Floyd delivered a modest punch to the coast, but the inland flooding became North Carolina’s worst natural disaster on record.

“I don’t think people realize how bad this is,” said Martin of the Fayetteville Fire Department. “This could be worse than Floyd.”

By Sunday, strong wins and saturated soils toppled trees through much of the central region of the state, knocking out power to nearly 700,000 homes. In Raleigh, the dam at Lake Benson was breached Saturday night. Three counties have lost water systems and 911 centers are down in five counties.

“I want the rest of the nation to know: We need your help,” North Carolina Gov. Pat McCrory said at a news conference.

Social video shows Hurricane Matthew bringing heavy rain and strong winds to Savannah, Ga., and Mount Pleasant, S.C., as the storm makes its way along the coastline. (Claritza Jimenez/The Washington Post)

As with Floyd, Matthew follows a prolonged period of rain in eastern and central North Carolina. Floodwaters in areas around Fayetteville, Windsor and Greenville had started to recede.

Portions of interstates 95 and 40, as well as several state highways, were shut down. In Fayetteville, the water came up so fast Saturday that county and city crews had trouble keeping up with road closures.

“The police, fire and rescue folks can’t block them off as quickly as they’re flooding,” city spokesman Kevin Arata said.

Matthew caused plenty of chaos before it reached the Carolinas. In Daytona Beach, Fla., bridges reopened Saturday morning, and residents returned to their homes to find cracked walls and broken windows. The Daytona Beach pier remained intact, but debris and sand littered the boardwalk, and the steel railing that wraps around it was bent and twisted.

“It’s crazy to see how strong Mother Nature is,” resident John Hogeland said as he surveyed the damage.

In St. Augustine, Fla., which was founded in 1565 and is the country’s oldest city, officials were trying to restore power, sewerage and water service. One fire and rescue official there estimated that St. Johns County alone suffered more than $2 billion in damage.

National Guard troopers in camouflage stopped motorists from driving across the Bridge of Lions to the barrier island, though people on foot or bicycles could go through. Residents who had evacuated the city proper could not return home.

“The National Guard is securing the city,” Mayor Nancy Shaver said. “It’s about safety.”

Two states to the north, the winds over Charleston had increased in strength around midnight Friday. Soon power lines came down, blocking roadways. Burglar and fire alarms affected by the loss of electricity sounded across the city. As of 7:30 a.m. Saturday, the South Carolina Electric and Gas Co. reported more than 150,000 customers without power, mainly in Charleston and Beaufort counties.

Around the same time, the National Weather Service estimated the storm surge for Charleston at about six feet. Bridges became unsafe for travel, and local officials suspended emergency medical services.

“It’s going to get to the point where we cannot send help to anybody no matter what the situation,” warned Cathy Hayne, chief of operations with the Charleston County Emergency Management Department.

Most downtown streets in the city, founded in 1670 and known for its antebellum architecture, became rivers after the deluge. Homes throughout Charleston’s historic district had been protected with plywood and lined with sandbags. By afternoon, the initial floodwaters had retreated, leaving mud in the streets as residents wandered neighborhoods to check out the mess.

Streetside crape myrtles leaned precariously over the roadways. The storm had torn awnings from storefronts. The South Carolina Department of Transportation closed Charleston’s Arthur Ravenel Jr. Bridge so inspectors could look for problems.

Mark Wilbert, director of emergency management in Charleston, said that the city — a finger of land between the Ashley and Cooper rivers — had not suffered any major building damage and that those tidal rivers would pull the floodwaters back toward the ocean with every low tide.

“We’re pretty confident that, absent any more rain, we’ll see the water levels go down significantly,” Wilbert said.

The Red Cross reported Saturday that 6,600 people were staying in the 63 shelters open across South Carolina. More than 350,000 had evacuated the coast, Haley, the governor, said. Haley told evacuees that they should not plan on returning to their homes for two days as emergency crews venture out to assess damage.

“Now is when the frustration sets in,” she said. “What I am going to ask from you is patience. Most injuries, most fatalities occur after a storm.”

Charleston County emergency management officials said more than 100 roadways were blocked Saturday by fallen trees, power lines and flooding. Statewide, more than 437,000 residents were without electricity. Kiawah and Seabrook islands were inaccessible.

In low-lying Beaufort County, S.C., which includes Hilton Head and other barrier islands, rainfall during the day topped a foot in some locations. After the rain tapered off, damage assessments were hindered by road blockages — flooding in some areas, downed trees in others.

“Every couple hundred yards, you’ve got big 80-foot pine trees laying across the road. And they’re pine trees. I always thought they were kind of sturdy,” said Capt. Bob Bromage of the Beaufort County Sheriff’s Office.

Those who escaped the dangers of Hurricane Matthew on the coast faced threats online, according to the governor. South Carolina residents received emails promising updates on power outages. But those who clicked on the link provided in the emails inadvertently opened their computers to hackers, she said.

Ross reported from Carolina Beach, N.C. Achenbach reported from Washington. Chico Harlan, William Branigin, Angela Fritz and Jason Samenow in Washington; Arelis R. Hernández in Ormond Beach, Fla.; Renae Merle and Susan Cooper Eastman in St. Augustine, Fla.; Lacey McLaughlin in Daytona Beach, Fla.; Sharon Dunten in Brunswick, Ga.; and Camille Pendley in Atlanta contributed to this report.