Days after the storm formerly known as Hurricane Matthew moved out to sea, people far inland in the Carolinas faced new flood dangers Tuesday as officials warned residents along rain-soaked rivers to evacuate.

Crews worked for hours to try securing a dam in danger of breaking in Moore County, N.C., west of Fayetteville, Deputy Public Safety Director Scott Brooks said. He added that the evacuation ordered late Monday in that area was the second in the last three days.

Rescue teams were returning to work across eastern North Carolina as the deluge moved downstream toward the Atlantic Ocean. At least three rivers were forecast to reach record levels, some not cresting until Friday. Officials confirmed 15 storm-related deaths in the state, bringing the total of U.S. deaths to 27.

Gov. Pat McCrory also announced that a state trooper shot and killed a man in Lumberton as crews conducted emergency rescues. The governor said the trooper and two deputies encountered the man while going through high water in a Humvee around 8 p.m. Monday, adding that it happened in "very difficult circumstances."

The State Bureau of Investigation is investigating the shooting. The agency did not immediately respond to messages from The Associated Press seeking more information.

The National Weather Service issued a flash flood warning for the area in Moore County, as well as Hoke and Cumberland counties because of the danger a dam failure would pose. The full extent of the disaster in North Carolina is still unclear, but it appears that thousands of homes were damaged, and many more remain in danger of flooding.

McCrory warned that for many parts of his state, conditions over the next three days "will be extremely dangerous."

The NWS also posted flood warnings for rivers in northeastern South Carolina after Hurricane Matthew dumped as much as 15 inches of rain.

Forecasters said the Little Pee Dee River at Gallivants Ferry in Horry County was seven feet above flood stage and record flooding was predicted there. Major flooding was also forecast along the Waccamaw River in Conway. The Lynches River at Effingham in Florence County was more than three feet above flood stage while the Black River at Kingstree was more than four feet above flood stage.

Among the new deaths confirmed Tuesday in North Carolina, a driver was heading home from work when a tree fell on his vehicle in Wake County, McCrory said. The storm killed more than 500 people in Haiti.

With helicopters overseeing the rescue operation from above, volunteer firefighters turned their military-surplus truck with 4-foot tires into the dark flood waters in Lumberton, cruising past a mortuary, grocery and homes that flooded.

They joined U.S. Marshals and water rescue teams from as far away as New York and New Jersey focused Monday on retrieving about 1,500 residents who were trapped when the Lumber River unexpectedly rushed out of its banks, up their stairways and into buildings.

The half-dozen men from the nearby town of Rayham spent about 10 hours Monday at the rescue work aboard their truck -- usually used for fighting brush fires in this swampy, rural southeast corner of North Carolina. They primarily located and ferried to safety rescued residents in inflated dinghies or bass boats to meet the truck on the neighborhood's main street.

"We've got it nowhere near this bad," said Jimmy Hunt Jr., son of the chief of the volunteer fire department in Rayham.

Robert Barnhill, 83, and his wife Katie, 81, left everything inside their Lumberton home but their medications, a couple of blankets and a pillow.

"The water's up to the porch now, so it's got one more step to go" before entering their home of 35 years, Robert Barnhill said after being rescued Monday afternoon. "I've never seen a flood like this before."

"I've been here right at 28 years," county Emergency Management Director Stephanie Chavis said. "This seems to be the worst one we've had in my career."

In many areas, Matthew's aftermath was compared to Hurricane Floyd, which caused $3 billion in damage and destroyed 7,000 homes as it skirted the coast in 1999.

Officials were concerned that other cities could suffer the fate of Lumberton, a community of 22,000 people about 80 miles from the ocean. With electricity cut off in the storm's wake, there was virtually no gasoline, water or food for sale.

The Rev. Volley Hanson worried that stress from the lack of running water and electricity might push people over the edge. Robeson County, which includes Lumberton, had North Carolina's highest violent crime rate in 2014.

"The cash is going to be running out. We've already got street vendors hawking water, Cokes and cigarettes. Cigarettes are at seven bucks a pack," Hanson said. "It's nuts here, and it's going to get worse."

The Lumber River crested 4 feet above its record level Sunday in Lumberton and was forecast to remain there until Saturday. A levee appeared to fail early Monday, but officials later concluded that floodwaters had flowed around it.

River flooding was happening in other places, too. In the tiny town of Nichols, South Carolina, downstream from Lumberton, at least 100 people spent the night on the third floor of the town hall.

Interstate 95 -- a major artery for the East Coast -- was closed in Lumberton and engineers had no estimate on when it would reopen. Driving was difficult, if not impossible because hundreds of roads were closed, in some cases isolating entire towns. Dozens of school districts and East Carolina University canceled classes for the entire week. Nearly 1 million people in North Carolina and South Carolina were without power, two days after the eye of the hurricane moved out to sea.

Matthew's flooding in North Carolina was made worse by heavy rains in September. Many areas east of I-95 got at least twice their normal amount of rain in September, in part because the remnants of Tropical Storm Julia parked off the coast for several days.

The Associated Press contributed to this report.