(CNN) - Amy Stevens said it was 85 degrees and sunny in Georgetown County, South Carolina, on Tuesday, but no one was letting their guard down.
"It's a beautiful day," she said in a phone interview. "It's hard to imagine. But flood waters are on the way."
Indeed, thousands of people are being urged to evacuate ahead of historic flooding in an area where multiple swollen rivers converge, with authorities predicting the possibility of between eight and 10 feet of water as early as Wednesday night into Thursday morning.
"There's really no reason whatsoever that I know of not to evacuate," Georgetown County Emergency Management Director Sam Hodge said during a Facebook Live update Tuesday afternoon.
Patients from Tidelands Georgetown Memorial Hospital in Georgetown have been relocated to the Waccamaw Community Hospital in Murrells Inlet, according to Stevens, a spokeswoman for Tideslands Health. But emergency operations were expected to continue.
It's the hospital's first evacuation in about 70 years, she said.
Hodge said waters were already rising in the county, with moderate flooding expected Tuesday evening and reaching major flood stage over the next couple of days. Those conditions should peak on Friday and continue into next week.
"This is not going to be a short-term event," Hodge said. "Life is not going to be normal like we see it in Georgetown County town for the next week or so."
At Graham's Landing on Front, a restaurant in Georgetown, part-owner Robert Maring said the community has spent weeks on edge anticipating Florence's arrival and now the threat of major flooding.
"It's like being stalked by a turtle," he said, as workers used sandbags and sheets of plastic to guard the business against rising waters.
"We're preparing to be about this deep," Maring said, holding his hand to his chest, or about five feet.
Jaclyn Valentine said she planned to evacuate her home in Georgetown Tuesday evening to stay with a daughter. She said up to 10 feet of water is expected around her home, essentially covering the first floor.
"Once this flood rises, we'll be trapped in this little town," she told HLN Tuesday afternoon. "Actually, right now, there's no place to go. The hotels are full. Our two hotels in town have been been evacuated and closed down. Our bridge is going to be closed down. ... There's no place to go."
There were thousands of other residents in a similar situation, Valentine said.
The county escaped the brunt of then-Hurricane Florence's wind, but it sits at the mouths of the Waccamaw, Great Pee Dee and Sampit rivers.
Parts of Georgetown County will see at least 10 feet of flooding, forecasters said. The flooding is expected to last through the weekend.
The Great Pee Dee and the larger Waccamaw River have already swollen to record levels upstream -- as demonstrated by the flooding 40 miles north in and around Conway, where the Waccamaw is still rising -- and that water is now traveling downstream at historic levels.
The crest was forecast for about midday Wednesday at 22 feet, which would surpass a previous record of 17.9 feet during Hurricane Matthew.
There is no benchmark for comparison, not even the destruction wrought by Hurricane Matthew two years ago, Georgetown County Administrator Sel Hemingway said.
Making matters worse is the potential for tides to exacerbate floodwater levels. Normally, from low tide to high tide, Georgetown sees about a 3-foot difference in the water level where the Great Pee Dee River meets Winyah Bay.
Monday night's full moon means high tides will be even higher. If the rivers hit peak crest during a high tide, flooding will spread even farther into the city.
Hemingway said water levels were expected to be at their highest later in the week. The South Carolina Department of Natural Resources anticipates the waters will crest late Wednesday night and into early Thursday morning, Hemingway said.
How the city is preparing
All of the preparation comes more than a week after Florence made landfall and pummeled the Carolinas with wind and rain.
On Monday, the death toll from the storm rose to 47 after North Carolina Gov. Roy Cooper's office said three more deaths had been confirmed in that state.
The rainfall that Florence dumped on North Carolina has been crawling downriver for more than two weeks. It's now set to inundate the homes and businesses belonging to Georgetown County's more than 61,000 people -- almost 8,000 of whom are being urged to evacuate.
A significant portion of the city of Georgetown is expected to be under water.
Critical infrastructure is already being prepared and hardened. Along Highway 17, which connects Georgetown to the nearby South Carolina coast and its beaches, flood barriers are being erected.
According to South Carolina Transportation Secretary Christy Hall, the agency is using aquadams along portions of Highway 17 to keep water off the road and keep the highway open as long as possible. But officials believe it will need to close at some point.
Officials worry the flooding could wash away the portion of the highway that links the bridges spanning the Great Pee Dee and Waccamaw rivers.
As a precaution, the South Carolina National Guard is building a floating ribbon bridge, capable of carrying heavy equipment, across the Waccamaw River.
Experts have arrived to monitor the flooding and keep an eye on the bridges, Deputy Secretary of Engineering for the Department of Transportation Leland Colvin said. The bridges won't reopen until they've been inspected following the flooding.
The US Army Corps of Engineers is also on location, ready to respond, help and offer support in whatever way the state or FEMA ask, according to Brigadier General Diana Holland, commander of the Army Corps South Atlantic Division.
"We know there will be a significant rise in the rivers, where they converge here," she said. "We'll just have to see."
All Georgetown County schools were closed Monday until further notice. Several are "at risk for substantial flooding damage," county officials say. Two of them, Georgetown High School and Waccamaw Middle School, have opened as pet-friendly shelters.
The Georgetown County Water and Sewer District is also scrambling to prepare. The Waccamaw River, which supplies drinking water for the county, will soon contain dangerous pollutants from the floodwater.
Ray Gagnon, executive director of the water district, told reporters that the district is working to protect all of its facilities in the "inundation zone," and preparing other sources of water, including aquifers, recovery wells, groundwater wells and the county's interconnect with the nearby Grand Strand Water and Sewer Authority.
Sandbags are also being distributed -- up to 10 per household -- but the county warned on its Facebook page, "Keep in mind that sandbags will not seal out water."
A waiting game
Thomas Cafe sits on Front Street, the main drag in Georgetown. It looks almost exactly like did it did when it opened in 1929.
The menu and the booths are original, as is most of the decor -- even the refrigerator.
In its 89-year history, it has never flooded before. Matthew's floodwater reached only to its back door.
"We're expected to get water in this time," said Olivia Goins, who has waited tables there for five years.
On Tuesday, the cafe won't be serving its famous $10.95 shrimp and grits. It will close for one of the few times in its history so employees can remove the fridges and freezers ahead of the flood.
Like many residents and business owners in the city, they're trying to prepare in any way they can, but in the end, there's not much they can do.
"Water is water," Goins said.
Chuck Richardson spent Monday afternoon trying to fortify a building he owns in Georgetown with large planks of plywood, sandbags and a rubber membrane. He hoped it would be enough.
"Might not keep the water out," he said, "but hopefully keep the fish and crabs and mud out."
He's had plenty of experience preparing for these types of events.
"Oh yeah, we're pros at this," he joked. "We try to do it at least once a year, whether we want to or not."
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