Hurricane Florence has become even stronger over the Atlantic Ocean.
Forecasters at the National Hurricane Center say Florence rapidly intensified Monday morning to a potentially catastrophic Category 4 hurricane with maximum sustained winds near 130 mph (195 kph).
Florence had reached Category 3 strength earlier Monday, but data from hurricane hunter aircraft indicate the storm is quickly getting stronger as it moves over warm Atlantic waters.
Forecasters say the hurricane’s strength is expected to fluctuate but it still will be a dangerous storm by the time it reaches the coast of South Carolina or North Carolina on Thursday.
As of noon EDT, Florence was centered about 575 miles (925 kilometers) south-southeast of Bermuda, moving west at 13 mph (20 kph).
Forecasters said Hurricane Helene was strengthening far from land over the open Atlantic, centred about 375 miles (600 kilometres) west of the southernmost Cabo Verde Islands.
WATCH: Store shelves empty as Hurricane Florence threatens to slam North Carolina head-on
Forecasters said it is too early to know the exact path Florence will take but warned that it could roll ashore in the Carolinas by Thursday. But authorities were taking no chances as the governors of North and South Carolina and Virginia declared states of emergency far ahead of the approaching storm.
Navy ships off Virginia’s coast are getting set to sail out of the path of the powerful hurricane, one North Carolina University has cancelled classes and people have begun stocking up on plywood, bottled water and other supplies even with Florence still far out at sea southeast of Bermuda.
North Carolina’s governor urged residents on Monday to get prepared for Hurricane Florence as forecasters predict the state could be in the “bullseye” of the storm.
Gov. Roy Cooper said the state is bracing for three threats from Hurricane Florence: ocean surges along the coast, strong winds, and island flooding. He said North Carolina is “bracing for a hard hit” in what forecasters say will be a statewide event.
Evacuations of coastal communities began Monday and are expected to continue over the next few days.
Cooper said 200 National Guard troops have already been activated. He’s also asked U.S. President Donald Trump for a disaster declaration so the state can get federal help as quickly as possible.
WATCH: ‘This is not our first rodeo’ — Charleston mayor says past storms have prepared them for Florence
In Charleston, South Carolina, along the coast, city officials offered sandbags to residents. Myrtle Beach Mayor Brenda Bethune urged people to secure their homes but said it was too early to know if evacuations will be ordered.
Myrtle Beach hardware stores and supermarkets were busy ringing up sales of bottled water, plywood and generators.
WATCH: Hurricane Florence: Charleston mayor says ‘it’s better to be safe than sorry’
“Literally, they are filling buggies full of water, shopping carts full of water,” Ryan Deeck, grocery department manager at a Walmart, told The Sun News. “They’re coming in and buying water and plates, and that’s about all they’re buying.”
North Carolina officials started getting bulldozers and chainsaws ready.
In Jacksonville, North Carolina, about 20 miles (32 kilometres) from the coast, some residents picked up hurricane supplies during their normal weekend shopping, The Daily News reported. Ilija Cesal told the newspaper he wouldn’t worry about buying extra water or other supplies for a few more days.
“I’ll see by Wednesday how that goes — we got over 48 hours before that happens,” Cesal said.
As Hurricane Florence approaches the East Coast, the University of North Carolina at Wilmington cancelled classes and encouraged its students to leave campus for a safer location.
WATCH: Virginia Governor explains how state is preparing for Hurricane Florence
In southeast Virginia, Naval Station Norfolk told its employees they should not leave their vehicles parked at the sprawling base in coming days because of the flood threat. The Navy planned to send ships from the Hampton Roads area of Virginia out to sea.
Florida-based Carnival Cruise Line re-routed its cruise ships.
WATCH: Charleston warns residents to get ready for Hurricane Florence