Hurricane Florence’s leading edge battered the Carolina coast on Thursday,  as the hulking storm closed in with 105 mph winds for a drenching siege that could last all weekend.

Forecasters said conditions would only get more lethal as the storm pushes ashore early Friday near the North Carolina-South Carolina line and makes its way slowly inland.

Its surge of ocean water could cover all but a sliver of the Carolina coast under as much as 13 feet, and days of downpours could unload more than three feet of rain, touching off severe flooding.

Florence’s winds weakened as it drew closer to land, dropping from a peak of 140 mph earlier in the week, and the hurricane was downgraded from a terrifying Category 4 to a 2.

But North Carolina governor Roy Cooper warned: “Don’t relax, don’t get complacent. Stay on guard. This is a powerful storm that can kill. Today the threat becomes a reality.”

Forecasters said that given the storm’s size and sluggish track, it could cause epic damage akin to what the Houston area saw during Hurricane Harvey just over a year ago, with floodwaters swamping homes and businesses and washing over industrial waste sites and pig-manure ponds.

“It truly is really about the whole size of this storm,” National Hurricane Center director Ken Graham said.

“The larger and the slower the storm is, the greater the threat and the impact – and we have that.”

The hurricane was seen as a major test for the Federal Emergency Management Agency, which was heavily criticised as sluggish and unprepared for Hurricane Maria in Puerto Rico last year.

As Florence drew near, President Donald Trump tweeted that the Federal Emergency Management Agency and first responders are “supplied and ready,” and he disputed the official conclusion that nearly 3,000 people died in Puerto Rico, claiming the figure was a Democratic plot to make him look bad.

Schools and businesses closed as far south as Georgia, airlines cancelled about 1,200 flights and counting, and coastal towns in the Carolinas were largely emptied.

Around midday, Spanish moss blew sideways in the trees as the winds increased in Wilmington, and floating docks bounced atop swells at Morehead City.

Hurricane Florence
Hurricane Florence churns over the Atlantic as seen from the International Space Station (Alexander Gerst/ESA/NASA via AP)

Some of the few people still left in Nags Head on the Outer Banks took photos of angry waves topped with white froth.

By early afternoon, utilities reported about 12,000 homes and businesses had lost power.

More than 1.7 million people in the Carolinas and Virginia were warned to evacuate over the past few days, and the homes of about 10 million were under watches or warnings for the hurricane or tropical storm conditions.

Homeless after losing her job three months ago, 25-year-old Brittany Jones went to a storm shelter at a high school near Raleigh. She said a hurricane has a way of bringing everyone to the same level.

“It doesn’t matter how much money you have or how many generators you have if you can’t get gas,” she said.

“Whether you have a house or not, when the storm comes it will bring everyone together. A storm can come and wipe your house out overnight.”

US hurricane
(PA Graphics)

Florence’s weakening as it neared the coast created tension between some who left home and authorities who worried that the storm could still be deadly.

Frustrated after evacuating his beach home for a storm that was later downgraded, retired nurse Frederick Fisher grumbled in the lobby of a Wilmington hotel several miles inland.

“Against my better judgment, due to emotionalism, I evacuated,” said Fisher, 74. “I’ve got four cats inside the house. If I can’t get back in a week, after a while they might turn on each other or trash the place.”

Hurricane Florence evacuations
People have been ordered to evacuate (Sean Rayford/AP)

Authorities rejected against any suggestion the storm’s threat was exaggerated.

The police chief of a barrier island in Florence’s bulls’-eye said he was asking for next-of-kin contact information from the few residents who refused to leave.

“I’m not going to put our personnel in harm’s way, especially for people that we’ve already told to evacuate,” Wrightsville Beach Police Chief Dan House said.