Mass evacuations were under way with Hurricane Florence forecast to smash into the Carolina coast this week as the most powerful storm ever to make landfall so far north along the Eastern Seaboard.

Bolstered by unusually warm waters, the Category 4 hurricane has gained power and speed at an alarming rate–raising the specter of homes and pig farms under up to three feet of water.

“Life threatening, catastrophic flash flooding and significant river flooding is likely over portions of the Carolinas and Mid-Atlantic states from late this week until early next week,” the National Hurricane Center said Tuesday evening.

“This storm is a monster. It’s big and it’s vicious. It is an extremely, dangerous, life-threatening, historic hurricane,” North Carolina Gov. Roy Cooper said.

“The waves and the wind this storm may bring is nothing like you’ve ever seen. Even if you’ve ridden out storms before, this one is different.”

Highways were converted to one-way roads to speed residents to safer ground as airlines began canceling flights. Long lines snaked through gas stations and at supermarket checkouts.

“There’s no water. There’s no juices. There’s no canned goods,” Kristin Harrington told the Associated Press as she shopped at a Walmart in Wilmington, N.C.

A storm surge warning was in effect from South Santee River, South Carolina, to Duck, North Carolina. “Preparations to protect life and property should be rushed to completion,” the National Hurricane Center warned.

Meteorologists fear that Hurricane Harvey-style rainfall could deluge the Carolinas causing massive freshwater flooding reminiscent of the devastation in Texas last year, which killed 68 people and caused $125 billion in damage.

Florence is expected to make a direct hit in the northernmost part of South Carolina or North Carolina. Rather than continuing to churn north along the coast, the hurricane is expected to strike the coast head-on and move inland, dumping vast quantities of water—perhaps more than 30 inches in places—as it slows down.

That trajectory is also likely to increase the storm surge on the coast. Landfall is expected around 2 a.m. Friday morning, at which point a surge is predicted that could exceed North Carolina’s record of 18 feet, which has stood since Hurricane Hazel in 1954. “This will be a worst-case scenario storm,” a spokesman for the Program for the Study of Developed Shorelines said.

Around 1.5 million residents and tourists soaking up the last of this season’s sunshine have been told to evacuate the coastal towns and beaches along sections of North and South Carolina as well as Virginia.

President Donald Trump declared a state of emergency in the Carolinas, opening the states to federal support. Virginia, Maryland, and Washington, D.C. also declared states of emergency.

Some local counties issued mandatory evacuations as the prognosis worsened late Monday. For much of coastal region, the evacuation orders were still voluntary but the governor pleaded with residents to be wary. “We encourage people to abide by evacuation orders issued by counties and not try to ride out this storm,” he said. “This is a major storm.”

Carolina Beach, 20 minutes south of Wilmington, was one of the places that announced a state of emergency and imposed a mandatory evacuation.

The town council ordered residents to be off the island by Tuesday night, with a curfew, ban on alcohol sales, and firearms restrictions imposed from Wednesday evening. Town Manager Michael Cramer warned that anyone refusing to flee would be stranded without power. “It will not be days we will be out of power, it may be a week or more,” he said, according to the Wilmington-based Star News.

On the Outer Banks, residents were joining long lines at gas stations and plotting escape routes. The Ocracoke ferry was offering free rides to anyone fleeing the islands. “This is the biggest storm to head for our coast in decades,” said Harold Thomas, the ferry director. “We hope everyone on Ocracoke Island will take heed and leave as soon as possible.”

Further north on the Outer Banks, the famous herd of wild horses will be left to ride out the storm. “The horses have lived on this barrier island for 500 years, and they are well equipped to deal with rough weather,” the Corolla Wild Horse Fund said Monday. “They know where to go to stay high and dry and are probably in better shape right now than most of us humans who are scrambling with final preparations.”

The University of North Carolina has ordered all students and staff off the Wilmington campus. Those with nowhere else to go can seek shelter at the university’s campus at Asheville at the foot of the Appalachian Mountains in the far west of the state.

South Carolina also ordered hundreds of educational and medical facilities shuttered and hundreds of thousands of people evacuated. Gov. Henry McMaster told residents, who are well used to storm warnings, that Florence was expected to create more wind than Hurricane Hugo and more water than Hurricane Matthew, according to The State newspaper.

“We know the evacuation order I’m issuing will be inconvenient. But we’re not going to gamble with the lives of the people of South Carolina. Not a one," McMaster said.

If the storm continues as predicted, meteorologist Bob Henson said it would be the only hurricane on record to make Category 4 landfall so far north.