Hurricane Florence was more recently downgraded to a Category 2 storm.
Isaac, which had built to tropical storm status when its winds topped 39 mph on Saturday, has weakened to a depression over the eastern Caribbean sea with winds of 35 mph and is moving west at 15 mph, lashing the Lesser Antilles with rain squalls as of the 5 a.m. advisory.
"It can not be emphasized enough that the most serious hazard associated with slow-moving Florence is extremely heavy rainfall, which will cause disastrous flooding that will be spreading inland through the weekend", the National Hurricane Center said in its 5 a.m. update.
The danger came in the form of a massive storm surge.
Susan Faulkenberry Panousis has stayed in her Bald Head Island, North Carolina home during prior hurricanes, but not this time.More news: President Trump 'cancels' November trip to Ireland
Farther up the coast, in New Bern, about 150 people were waiting to be rescued from floods on the Neuse River, WXII-TV reported. Here's how things look so far this morning. "Currently ~150 awaiting rescue in New Bern", City Hall said on Twitter.
At least 12,000 people had taken refuge in 126 emergency shelters, Cooper said, with more facilities being opened.
He said that the hurricane could only be captured on a super-wide lens, even from 400 kilometres up.
The expected heavy rainfall would produce both flash flooding and river flooding that could in turn cause an environmental disaster, if the water inundates the region's many industrial waste sites and hog manure ponds.
North Carolina corrections officials said more than 3,000 people were relocated from prisons and juvenile detention centers in the path of Florence, and more than 300 county prisoners were transferred to state facilities.
"Catastrophic effects will be felt outside the center of the storm due to storm surge as high as 9 to 13 feet".More news: Almost 40 fires and explosions erupt in MA
And now, many more people, houses and buildings are set to endure hurricane-force winds, which extend 80 miles out from Florence's center.
A few hours after landfall, forecasters said Florence was slowly wobbling southwestward just off the coast of southern North Carolina. The city said two Federal Emergency Management Agency (Fema) teams were working on swift-water rescues and more were on the way.
Myrtle Beach, a SC beach resort, was deserted with empty streets, boarded up storefronts and very little traffic.
A state of emergency has been declared in five coastal states - North Carolina, South Carolina, Georgia, Maryland and Virginia. Duke Energy, a power company in the Carolinas, estimated that one million to three million customers could lose electricity because of the storm and that it could take weeks to restore.
Not everybody was heeding orders to evacuate, however.
The worst of the storm's fury had yet to reach coastal SC, where emergency managers said it was not too late for people to get out. As in past storm events, these animal are taken to other shelters including those in the NY area. "I'm not leaving him here".More news: Mac Miller Death Details, Dead for Hours, Drug Overdose
Some residents ignored calls to evacuate. "We're able", he said. "I learned from the past to keep the ice in the washing machine".