ANNAPOLIS, Maryland(AP) – Residents in parts of coastal North Carolina and Virginia experienced flooding Saturday after Tropical Storm Ophelia made landfall near a North Carolina barrier island, bringing rain, damaging winds and dangerous surges.

The storm came ashore near Emerald Isle with near-hurricane-strength winds of 70 mph (113 kph) at around 6:15 am but weakened as it travelled north Saturday, the US National Hurricane Center said. Ophelia is expected to sweep northeast Sunday along the mid-Atlantic coast up to New Jersey.

Videos from social media showed riverfront communities in North Carolina such as New Bern, Belhaven and Washington experiencing significant flooding. The extent of the damage was not immediately clear.

Even before it made landfall, the storm proved treacherous enough that five people had to be rescued by the Coast Guard on Friday night from a boat anchored down near the North Carolina coastline.

Ophelia promises a weekend of windy conditions and heavy rain as it churns up the East Coast, with the storm moving north at about 13 mph (21 kph) as of Saturday afternoon. Parts of North Carolina and Virginia can expect up to eight inches of rain (20 centimetres), with two to four inches (five to 10 centimeters) forecast in the rest of the mid-Atlantic region through Sunday. Some New Jersey shore communities, including Sea Isle City, had already experienced some flooding Saturday.

Philippe Papin, a hurricane specialist with the National Hurricane Center, said the primary risk of the storm system over the next couple of days will be the threat of floods from the rain.

“There have been tropical storm-force winds observed, but those are starting to gradually subside as the system moves further inland,” Papin said in an interview early Saturday. “However, there is a significant flooding rainfall threat for a large portion of eastern North Carolina into southern Virginia over the next 12 to 24 hours.”

Power outages spread through more states beyond North Carolina, where tens of thousands of homes and businesses remained without electricity across several eastern counties as of Saturday afternoon, according to poweroutage.us, which tracks utility reports.

“When you have that slow-moving storm with several inches of rain, coupled with a gust that gets to 30, 40 miles per hour, that’s enough to bring down a tree or to bring down limbs,” Duke Energy spokesperson Jeff Brooks told WTVD-TV on Saturday. “And that’s what we’ve seen in most of the areas where we’ve experienced outages.”

Brian Haines, a spokesperson for the North Carolina Division of Emergency Management, said there were also reports of downed trees, but no major road closings.

“North Carolina Emergency Management continues to monitor the situation and to work with our county partners, who are currently not reporting any resource needs,” Haines said Saturday morning.

A storm surge warning, indicating danger from rising ocean water pushed inland by Ophelia, was in effect from Ocracoke Inlet, North Carolina, to Chincoteague, Virginia. Surges between three and five feet (0.9 and 1.5 metres) were forecast in some areas. A tropical storm warning was issued from Cape Fear, North Carolina, to Fenwick Island, Delaware.

Five people, including three children 10 or younger, needed the Coast Guard’s help on the water when conditions worsened Friday. They were aboard a 38-foot (12-metre) catamaran anchored in Lookout Bight in Cape Lookout, North Carolina, stuck in choppy water with strong winds.