Why the Storm Surge of Hurricane Florence Was So Dangerous

As Hurricane Florence took aim at the East Coast of the U.S. on Thursday, Sept. 13, 2018, North Carolina Gov. Roy Cooper stood before news cameras and issued a stern warning in the most sober of terms: "This is a powerful storm that can kill. Now is the time to get yourself to a safe place and stay there." It was, and is, a simple fact: Hurricanes can kill you — in many, many ways.

Hurricane Florence began as a tropical depression on Aug. 3, 2018, near Cape Verde, but eventually topped out as a Category 4 hurricane. According to the Saffir-Simpson Hurricane Wind Scale, a Category 4 has maximum sustained winds of 156 miles (251 kilometers) per hour.

The major hurricane packed sustained winds of 140 mph (225 kph) Wednesday night before they dropped to 105 mph (168 kph)when it was downgraded to a Category 2. But as the storm approached the North Carolina coast, the area covered by hurricane-force winds doubled, meaning more people felt the impacts of the winds that were 74 mph (119 kph) or greater.

The Hurricane Florence Surge

Weakening winds shouldn't ease anyone in an impact zone because, as Hurricane Florence proved, the rain and storm surge can be catastrophic.

The storm surge — essentially the water pushed ashore by all that wind — was predicted to be up as high as 13 feet (3.9 meters). That's 13 feet higher than the water level normally would be. Experts predicted that when Florence made landfall, it would regain strength and stall over inland North and South Carolina on Friday afternoon, dumping torrential rainfall — as much as 40 inches (1 meter) in some areas.

The rain and storm surge of 9 to 13 feet resulted in life-threatening flooding, particularly along Eastern North Carolina. The Cape Fear River flooded Currie and Canetuck. Hurricane Florence also broke the storm tide record previously held by Hurricane Matthew. According to the National Weather Service, the storm hit North Carolina with 20 to 30 inches of rain.

By Sept. 14, 2018, forecasters had downgraded Hurricane Florence to Tropical Storm Florence, but it continued to bring freshwater flooding to the Carolinas.

Why Is a Storm Surge Dangerous?

According to the National Weather Service, drowning from this type of storm surge, which can travel several miles inland, is the leading cause of death related to U.S. hurricanes. "If you're looking at a 6- to 9-foot surge ... you're not going to get out of there. You're done," says Carl Parker, a hurricane specialist at The Weather Channel. "It's really important to remember that water has tremendous power, tremendous force. It can very easily destroy things."

The wind and the surging seas by themselves are deadly. But that's just the tip of what a hurricane can do.

"There are a lot of different threats," Parker says. "Rainfall flooding actually causes about a quarter of the fatalities. That can actually hit you from both ends. If you're looking at these inlets ... the rivers are filling up from all this heavy rainfall, the waters are trying to run out to the ocean, and at the same time water's coming into the ocean, so that magnifies that water-level rise in those areas."

Drowning from the rains that Parker describes, the ones that swell inlets and rivers, is the second-leading cause of death from hurricanes, according to the NWS. The rains, and the flooding they cause, can go on for days after the storm has passed.

The threats to life continue, too, in many different forms.

It's More Than Just Wind and Water

"This is not going to be a glancing blow," Jeff Byard, associate administrator for response and recovery at the Federal Emergency Management Agency, said at the time in a press conference. "This is not going to be one of those storms that hits and moves out to sea. This is going to be a Mike Tyson punch to the Carolina coast."

According to the National Hurricane Center, 90 percent of U.S. deaths in hurricanes come from water and severe flooding. Other causes? The New York Times listed some after Hurricane Sandy ripped through in 2012:

A 23-year-old woman died when she went outside to take pictures of the devastation and stepped on a live power line.
A 28-year-old Staten Island man led his family to safety in the attic, but he returned to the basement where he was likely electrocuted.
A 50-year-old woman in Rockaway Park, Queens, cut her arm while trying to shut off the gas during the storm and bled to death.
A 10-by-10 foot (3-by-3 meter) section of roof from a mobile home crashed through the windshield of a car in Kerhonkson, a northern New York suburb, killing a 69-year-old woman.
A 75-year-old man and his 73-year-old wife were found dead in Ulster County, north of New York, dead from carbon monoxide poisoning from a generator they used to power their home during the storm.

Power outages pose a major problem, as well. At the time, Duke Power expected up to 3 million customers in North and South Carolina could lose power — that's 75 percent of its customer base in the two states. "The magnitude of the storm is beyond what we have seen in years," Howard Fowler, Duke Energy's incident commander, said in a statement.

To prepare, the company had more than 20,000 people in place to restore power — the largest resource mobilization ever for Duke Energy. "Despite our workforce, customers should continue to make plans for their homes and facilities," Fowler said. "It's important for people to know this is no ordinary storm and customers could be without power for a very long time — not days, but weeks."

The Biggest Threat

It's not just significant flooding that poses a threat to life. Outside of Mother Nature, it's also the fact that some don't move from the path of a hurricane. While sometimes it's the choice of people not to leave, it is also important to note that some people are not able to leave.

Government officials asked people to leave. "As we all know, this is one of the largest, most devastating storms in the history of the east coast of the United States," North Myrtle Beach Mayor Marilyn Hatley said on CNN on Sept. 12. "It is so important that people listen to the mandatory evacuation ... we have been begging people to leave. Once those winds get above 40 miles per hour, we can't send our emergency officer out to help you."

Millions of people evacuated more than 300 miles of coastline of North Carolina, South Carolina, Georgia and Virginia. Some decided to stay; others had no choice but to stay.