With mandatory evacuations already issued for parts of three East Coast states, millions of Americans are preparing for what could become one of the most catastrophic hurricanes to hit the Eastern Seaboard in decades.
Hurricane Florence's top winds dipped to 130 mph Tuesday morning, but it remained a powerful Category 4 storm.
"Re-strengthening is forecast to occur during the next day or so, and Florence is expected to be an extremely dangerous major hurricane through Thursday night," the National Hurricane Center said Tuesday morning.
It is forecast to close in on North or South Carolina on Thursday, hitting a stretch of coastline that's vulnerable to rising sea levels due to climate change.
"Please be prepared, be careful and be SAFE!" President Donald Trump tweetedMonday evening.
Florence could hit the Carolinas harder than any hurricane since Hazel packed 130 mph -- 209 kph -- winds in 1954. That Category 4 storm destroyed 15,000 buildings and killed 19 people in North Carolina. In the six decades since then, many thousands of people have moved to the coast.
The storm's first effects were already apparent on barrier islands as dangerous rip currents hit beaches and seawater flowed over a state highway -- the harbinger of a storm surge that could wipe out dunes and submerge entire communities. Watches were already in effect Tuesday for a storm surge that could reach up to 12 feet at high tide on a stretch from Cape Fear to Cape Lookout in North Carolina, forecasters said.
A hurricane watch was in effect for Edisto Beach, South Carolina, to Virginia's southern border, and the first hurricane-force winds arriving late Thursday.
South Carolina's governor ordered the state's entire coastline to be evacuated starting at noon Tuesday and predicted that 1 million people would flee. CBS News correspondent David Begnaud reports that lanes, at noon, will be reversed on four of the largest roads leading to the South Carolina coast, so cars will only be able to drive inland.
Similar evacuations are happening all the way up to Virginia, where the governor has ordered a mandatory evacuation for residents of some low-lying coastal areas.
A satellite image provided by the National Hurricane Center shows Hurricane Florence churning southeast of the Eastern Seaboard early on the morning of Sept. 11, 2018. NOAA/NWS/NATIONAL HURRICANE CENTER
National Hurricane Center Director Ken Graham warned that Florence was forecast to linger over the Carolinas once it reaches shore. People living well inland should prepare to lose power and endure flooding and other hazards, he warned.
"It's not just the coast," Graham said. "When you stall a system like this and it moves real slow, some of that rainfall can extend well away from the center."
For many people, the challenge could be finding a safe refuge: If Florence slows to a crawl just off the coast, it could bring torrential rains to the Appalachian mountains and as far away as West Virginia, causing flash floods, mudslides and other dangerous conditions.
Hurricane Florence path projections
The storm's potential path also includes half a dozen nuclear power plants, pits holding coal-ash and other industrial waste, and numerous hog farms that store animal waste in massive open-air lagoons.
Airlines, including American and Southwest, have started letting passengers change travel plans that take them into the hurricane's possible path.
A warm ocean is the fuel that powers hurricanes, and this area of the ocean is seeing temperatures peak near 85 degrees -- 30 Celsius, hurricane specialist Eric Blake wrote. And with little wind shear to pull the storm apart, Florence's hurricane-strength winds were expanding, reaching 40 miles -- 64 kilometers -- from the eye of the storm.
"Unfortunately, the models were right. Florence has rapidly intensified into an extremely dangerous hurricane," Blake wrote Monday evening, predicting that the hurricane's top sustained winds would approach the 157 mph (253 kph) threshold for a worst-case Category 5 scenario. Tuesday morning's forecast still supported this, the National Hurricane Center said.
By 8 a.m. Tuesday, Florence was centered about 950 miles, or 1,530 kilometers, east-southeast of Cape Fear, North Carolina, and moving west-northwest at 15 mph (24 kph). Its center will move between Bermuda and the Bahamas on Tuesday and Wednesday and approach the coast of South Carolina or North Carolina on Thursday.
Here is the latest 500 AM EDT forecast track and key messages for Hurricane Florence from the @NHC_Atlantic. Hurricane and Storm Surge Watches have been issued in association with major Hurricane Florence. #HurricaneFlorence #HurricanePreparedness #HurricanePrep pic.twitter.com/PcubmxWTkt— National Hurricane Center (@NHC_Atlantic) September 11, 2018
Preparations for Florence were intensifying up and down the densely populated coast. The parking lot has been full for three days at the Ace Hardware store in coastal Calabash, North Carolina, where manager Tom Roberts said he sold 150 gas cans in two hours Monday, along with generators, plywood, rope, manual can openers, sand bags and a plethora of other items.
"I've been doing this since 1983," Roberts said as he completed an order for another 18-wheeler full of supplies. "This is the craziest one."
Many newcomers have moved to the coast in the nearly 19 years since the last strong hurricane -- Floyd -- threatened the area. Roberts said he's telling them to get out of town.
"I'm telling them to go inland, but I'm worried about the rain and tornadoes too," Roberts said.
Several meteorologists said Florence could do what Hurricane Harvey did last year over Texas, dumping days of rain, although not quite as bad.
"I think this is very Harvey-esque," said University of Miami hurricane expert Brian McNoldy. "Normally, a landfalling tropical cyclone just keeps on going inland, gradually dissipating and raining itself out. But on rare occasions, the steering patterns can line up such that a storm slips into a dead zone between troughs and ridges."
On North Carolina's Outer Banks, Dawn Farrow Taylor, 50, was gathering photos and important documents and filling prescriptions Monday before heading inland. She grew up on the island chain, and says this will be only the second time she's evacuated.
"I don't think many of us have ever been through a Category 4. And out here we're so fragile. We're just a strip of land -- we're a barrier island," she said.
North Carolina Gov. Roy Cooper said his state was "in the bullseye" of the storm and urged people to "get ready now."
An evacuation order from Virginia Gov. Ralph Northam applies to about 245,000 people, including parts of the Hampton Roads area and Eastern Shore.
Two other storms were spinning in the Atlantic. Hurricane Isaac was expected to lose strength as it reaches the Caribbean, and Helene, much farther out to sea, may veer northward into the open ocean as the 2018 hurricane season reaches its peak.
In the Pacific, Hurricane Olivia triggered warnings for multiple Hawaiian islands as it blew west toward an arrival over the state as soon as late Tuesday or early Wednesday.
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