Police in Wilmington, North Carolina, near where the hurricane made landfall, said a mother and her infant were killed when a tree fell on their house.
The monster storm felled trees all around Wilmington, causing many more close calls and damaging homes and cars.
Also, one person was killed while plugging in a generator, and a man was knocked to the ground while outside and died, authorities said.
Other looters, who were not named, were caught breaking into private homes, police said.
For people living inland in the Carolinas, the moment of maximum peril from flash flooding could arrive days later, because it takes time for rainwater to drain into rivers and for those streams to crest.
As the storm moves inland, forecasters warned, the surge could cover all but a sliver of the Carolina coast under as much as 11 feet of ocean water, and days of downpours could unload more than 3 feet of rain, touching off severe flooding. If confirmed by the National Weather Service, this number would break the state record for rainfall from a tropical cyclone. Large, battering waves will ride atop this surge.
Meanwhile, the National Hurricane Center continues to track Tropical Storm Isaac as it continues to move west in the Caribbean. "It's just going to be painfully slow". He said parts of North Carolina had seen storm surges - the bulge of seawater pushed ashore by the hurricane - as high as 10 feet.
Fox News correspondent Steve Harrigan reported Friday afternoon in extreme wind and rain from Hurricane Florence in North Topsail Beach, North Carolina, which is bearing the brunt of the storm's impact. "People don't need to come back and make things more crowded and more hard to ensure safety".
As of 11 a.m. EDT, Florence was centered about 145 miles (230 kilometers) southeast of Wilmington, its forward movement slowed to 10 mph (17 kph).
"We are not going to make it, '" Cherry said.
Coastal North Carolina felt the first bite of Hurricane Florence on Thursday as winds began to rise, a prelude to the slow-moving tempest that forecasters warned would cause catastrophic flooding across a wide swath of the USA southeast.
The NHC described Florence as a "slow mover" and said it had the potential to dump historic amounts of rainfall on North and SC, as much as 40 inches (one meter) in some places. Shortly afterward, the National Weather Service reported wind gusts to 105 miles per hour at Wilmington International Airport, the highest wind gust measured in Wilmington since Hurricane Helene hit the port city in 1958.
North Carolina Gov. Roy Cooper, D, said the state was facing "an extremely unsafe situation, and it's getting worse" as the hurricane continued its assault.
North Carolina Gov. Roy Cooper urged residents to remain alert despite changing forecasts.
Weather Underground meteorology director Jeff Masters said Florence eventually could strike as merely a Category 1 hurricane with winds less than 100 miles per hour (160 kph), but that's still enough to cause at least $1 billion in damage.
Airlines canceled more than 2,100 flights through Sunday.
The Governor's Office has activated the North Carolina Disaster Relief Fund, which has been used in previous disasters, to accept donations to support North Carolina's response to Hurricane Florence.
"Very eerie, the wind howling, the rain blowing sideways, debris flying", said Orsa, who lives nearby and feared splintering trees would pummel her house.