ANNAPOLIS, Md. — Residents of 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 at around 6:15 a.m. but was expected to weaken as it turns north Saturday and then shifts northeast Sunday, the U.S. National Hurricane Center said, noting the maximum sustained winds had dropped to 50 mph by midmorning.

At 7:44 p.m. EDT, the center said that Ophelia had slowed to become a tropical depression, which is a weak form of a tropical storm, and all storm surge and tropical storm warnings had been discontinued.

Still, 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, five people had to be rescued by the Coast Guard on Friday night from a boat anchored 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 as of Saturday morning. Parts of North Carolina and Virginia can expect up to 8 inches of rain, with 2 to 4 inches forecast in the rest of the mid-Atlantic through Sunday.

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 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.”

Tens of thousands of homes and businesses were left without power across several eastern counties in North Carolina as of Saturday morning, 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 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.

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 from 3 to 5 feet were forecast in some areas. A tropical storm warning was issued from Cape Fear, North Carolina, to Fenwick Island, Delaware.

Storm surge hit areas of North Carolina, including New Bern, where part of the riverside downtown area saw flooding, local officials posted Saturday on social media.

The governors of North Carolina, Virginia and Maryland each declared a state of emergency Friday. Some schools closed early and several weekend events were canceled. In Washington, the Nationals baseball team postponed its Saturday game until Sunday. The North Carolina Ferry System has suspended service on all routes until conditions improve.

In the Baltimore region, the threat of the storm led organizers to cancel a number of events, including Saturday’s schedule at Artscape, horse racing at Pimlico Race Course, the Kunta Kinte Heritage Festival in Annapolis and the Trifecta Food Truck & Music Festival in Timonium.

The Maryland Renaissance Festival closed for the day.

Nancy Shoemaker and her husband, Bob, stopped by a park in Annapolis to pick up sandbags Friday. A surge of water during a storm last October washed away sandbags they had in their yard, which is next to the water.

“We’re hoping it won’t be that way this time,” Nancy Shoemaker said. “If we have a lot of wind and a lot of surge, it can look like the ocean out there, so that’s a problem.”

Annapolis water taxi driver Scott Bierman said service would be closed Saturday.

“We don’t operate when it’s going to endanger passengers and/or damage vessels,” Bierman said.

Dave Swain of Havre de Grace took his boat to Annapolis for the weekend. He had already secured the vessel at the City Dock early Friday afternoon and was prepared to ride out the storm.

“Really, you just have to make sure you’re tied up, and we’ve got bumpers out to make sure you don’t hit the docks,” Swain said. “It’s safer here than it would be to go back home right now, so we’re going to ride it out and see what happens.”

It is not uncommon for one or two tropical storms, or even hurricanes, to develop right off the East Coast each year, National Hurricane Center Director Michael Brennan said.

“We’re right at the peak of hurricane season. We can basically have storms form anywhere across much of the Atlantic basin,” Brennan said.

Scientists say climate change could result in hurricanes expanding their reach into midlatitude regions more often, making storms like this month’s Hurricane Lee more common.

One study simulated tropical cyclone tracks from pre-industrial times, modern times and a future with higher emissions. It found that hurricanes would track closer to the coasts, including around Boston, New York and Virginia, and be more likely to form along the Southeast coast.