USA TODAY International Edition
Why more damage now? It’s us, not the storms
Population growth along coast blamed for bigger impact
Three catastrophic hurricanes made U.S. landfall within 30 days of each other last year, causing more than $250 billion in losses.
By the time the winds died down and the floodwaters receded, Harvey, Irma and Maria were three of the five most destructive hurricanes in U.S. history – and 2017 was the costliest hurricane season ever.
But despite that exceptional cluster of storms, it’s not that hurricanes are getting stronger or more frequent that’s making them more expensive.
It’s that there’s more in the way for the storms to destroy.
As Hurricane Florence takes aim at the Carolinas this week, emergency management officials, meteorologists and insurance companies are looking as much at what’s in its path as they are
“There’s just more people in harm’s way, unfortunately. And not only are there more people, but we’re more affluent than our parents were.”
Phil Klotzbach a meteorologist at Colorado State University
the strength of the storm itself.
“The damage trend is obviously through-the-roof up, but most of that trend is due to population growth along the coastline,” said Phil Klotzbach, a meteorologist at Colorado State University. “There’s just more people in harm’s way, unfortunately. And not only are there more people, but we’re more affluent than our parents were.”
Those moving to the coasts are living in larger houses and own more cars, but their houses are also closer together. That means more impervious surfaces – such as roads and rooftops – and less area for the floodwaters to go.
So even as better construction methods have reduced the wind damage in many places – especially Florida, where Hurricane Andrew in 1992 inspired an overhaul of building codes – storm surge and flooding have taken over as the primary concern.
The frequency and intensity of hurricanes
“Florence is going to pose a triple threat of impacts in terms of high winds, coastal surge and then inland flood.” Steve Bowen a meteorologist with risk management firm Aon Benfield
have ebbed and flowed throughout the last century, but there has been no measurable increase in either over that time, several studies have found. If anything, in fact, there has been a slight decrease.
That doesn’t mean that climate change isn’t having an effect. As sea levels rise, storm surges are reaching farther inland.
And one study published in July showed that tropical cyclones across the world are actually slowing down. James Kossin of the National Oceanic and Atmospheric Administration found the average hurricane slowed about 10 percent from 1946 to 2016.
Slower hurricanes – such as Hurricane Harvey – can dump more rain on an area before moving on, adding to their destructive power.
Last year’s blitz of hurricanes was all the more unusual because the East Coast had enjoyed more than a decade of relative calm. Before Hurricane Harvey hit Texas in August 2017, the last major hurricane to hit the continental United States was Wilma in 2005.
Forecasters say it’s too soon to tell how destructive Hurricane Florence will be – but it has the potential to be on par with last year’s historically destructive storms. “Florence is going to pose a triple threat of impacts in terms of high winds, coastal surge and then inland flood,” said Steve Bowen, a meteorologist with risk management firm Aon Benfield.
He said much will depend on when, where and how fast it hits ground.
“You like to say in sports that it’s often a game of inches,” Bowen said. “In this case, it’s a matter of miles that can make a difference of billions of dollars.”