Warm water helped Helene intensify rapidly and sucked up moist air

Multiple Category 5 Hurricanees in the Last Century: Hurricanes, Floods, and Landfalls in North Carolina, and the Carolina Highways and Agricultural Fields

When a storm gets powerful very quickly like that, scientists call it rapid intensification. The data shows that hurricanes form in the Atlantic at a normal rate. Ken Graham, director of the National Weather Service, says that every Category 5 Hurricane in the last century was a tropical storm three days earlier.

“The major ingredient that is present in virtually all of the rapidly intensifying events is an incredibly warm ocean surface,” explains Jill Trepanier, a hurricane climatologist at Louisiana State University.

Along with floods, the persistent rains have created landslide conditions in western North Carolina, as member station WFAE reported. The National Weather Prediction Center has projected 12 inches for the region, well above the threshold for the area.

The storm dumped over eight inches of rain in the area, which caused serious damage to coastal homes and buildings, as well as agricultural fields.

In North Carolina, the rainfall totals Friday afternoon were staggering: 29.58 inches for Busick, N.C.; 24.20 for nearby Mount Mitchell State Park; about 13 inches in Boone, some 55 miles away.

Atlanta has had its highest two-day rain total on record over the past two days. The Georgia Climate Office tweeted on Friday that the area has already seen 11.12 inches of rain, beating a previous record of 9.59 set in 1886. Records started being kept in 1898.

In North Carolina, Helene produced unusually heavy winds — up to 140 mph — on land, the strongest observed in coastal North Carolina since the start of modern meteorological recordkeeping in the 19th century.

In Georgia, the death toll was 15, according to a spokesperson for Gov. Brian Kemp. There are at least two children among the dead. Two Georgians died in Wheeler County after their trailer was picked up by a tornado, an emergency management official said.

Several deaths were blamed on the high winds and tornadoes. Gov. Ron DeSantis said one person died on a highway in Tampa from a falling sign. A person died after a tree fell on their home.

In Tennessee, over 50 patients and staff were stuck on the roof of Unicoi County Hospital in Erwin, as floodwaters rose on Friday morning. They were rescued by the afternoon.

Meanwhile, the National Weather Service released an urgent warning through Friday afternoon urging anyone below the Lake Lure Dam near Ashville to evacuate immediately to higher ground, after concerns that the nearly century-old dam could fail.

Brigadier General Daniel Hibner with the Army Corps of Engineers said dam failures are to be expected in flash flooding events like this one. “It’s not uncommon to see a dam failure in an event like this,” he said at a press briefing. “I would be surprised if there weren’t multiple (dam failures) throughout this area.”

As of Friday evening, the dam remained intact. In a 6 p.m. ET update on social media, Rutherford County officials said the lake’s water levels were beginning to recede.

The National Hurricane Center predicted flooding, floods and death during the Saturday afternoon afternoon and evening of Friday afternoon–end hurricanes in Florida and the Appalachians

More than 4 million homes and businesses were without power on Friday afternoon in Florida, Georgia, North Carolina and South Carolina, according to poweroutage.us. By nightfall, that number had dipped to about 3.7 million.

For those relying on generators for power supply, the consumer safety officials advised people to keep them at least 20 feet away from the home to avoid deadly carbon monoxide poisoning. Improper portable generator use led to more deaths associated with 2020’s Hurricane Laura than the storm itself.

The storm surge reached more than 5 feet along the Gulf Coast of Florida Thursday night. Andrew Swan, 31, rode out the storm in Madeira Beach, Fla., watching over a friend’s house. He told the station water rushed into his house and he had to sleep on a counter with his legs over the stove.

The worst of the storm is over for most in the Southeast, and officials are warning people to keep an eye on the road after the storm.

Preliminary post-landfall modeling showed the storm surge reached 15 feet above ground level in the Big Bend area near Keaton Beach, Steinhatchee and Horseshoe Beach, the National Weather Service said.

The maximum winds were moving at 25 mph in an evening update from the National Hurricane Center. The storm made landfall Thursday night in Florida’s Big Bend region — the nexus of the Panhandle and peninsula in the state’s northwest — as a Category 4 hurricane with maximum sustained winds of 140 mph.

“The expected slow motion could result in significant flooding over the Ohio and Tennessee Valleys, and over the southern Appalachians through the weekend,” the center said in a late morning update.

The National Hurricane Center predicted life threatening flooding and damage in southern Appalachia into the evening.

Helene weakened to a post-tropical cyclone on Friday evening but continued to unleash “catastrophic” flooding in the southeastern U.S. and southern Appalachians, forecasters said.