Hurricane rating system fails to take account of deadly rain

Famous Roberts poses for a portrait as an SUV plowing through the water of the NC 41 outside of Trenton, N. C., on Monday, Sept. 17, 2018. Roberts chose to ride out the Hurricane Florence in Trenton, in part because the forecast strength had dropped from a Category 4 to Category 1. (AP Photo/Allen G. Breed)

TRENTON, North Carolina – As meteorologists downgraded Hurricane Florence from a powerful Category 4 storm to a category 2 and then Category 1, Wayne Mills thought he would be able to keep.

He regrets it. The Neuse River, normally 150 metres away, and licked near his home in New Bern, North Carolina, Sunday, even as the storm had “weakened” further.

People like Mills are lulled into thinking a hurricane is less dangerous if the rating of a storm is reduced. But these reviews are based on wind speed, not rainfall or storm surge, and water is responsible for 90 percent of the storm deaths .

Various meteorologists and disaster experts said that something needs to change with the 47-year-old Saffir-Simpson Hurricane Wind Scale to the actual risks in hurricanes. They point to Florence, last year’s Hurricane Harvey, 2012 Sandy and 2008’s Ike as the storms where the official Saffir-Simpson category is not at all about the danger, because of the emphasis on wind.

“The concept of ‘degraded’ or ‘weakened should be forever banned,” said University of Georgia meteorology professor Marshall Shepherd. “With Florence, I thought it was more dangerous after it was lowered to Category 2.”

It was a reduced category that helped convince Famous Roberts, a corrections officer at Trenton, to stay behind. “If a lot of people (we) do not think that it was actually so bad,” he said. “With the category drop … that is another factor why we did it.”

After a storm hits 74 mph (119 km / h) it is considered a Category 1 hurricane. The ratchets to reach the top-of-the-scale Category 5 157 mph (252 km / h). Florence hit as a Category 1 with 90 mph winds — not a particularly strong hurricane, but until now has dumped almost three feet of rain in parts of North Carolina and nearly two feet in parts of South Carolina.

“There is more to the story than the category” University of Miami hurricane researcher Brian McNoldy said. “While you might have a roof on your house, because” it’s just a Category 1,’ you may also be desperately hoping to be saved from that same roof because of the floods.”

Susan Cutter, director, Hazards and Vulnerability Research Institute at the University of South Carolina, said the hurricane center and National Weather Service “have not done a good job at communicating the risks associated with tropical systems after wind.”

One of the reasons, she said, is that it is much harder to explain to the other facts. Wind is simple.

The National Oceanic and Atmospheric Administration says it takes all hazards, including rain and storm surge seriously — and how she communicates. Forecasters were telling people four or five days before Florence found that it was a “major flooding event,” said Bill Lapenta, director of NOAA’s National Centers for Environmental Prediction, which the hurricane center.

When Florence wind weakened and fell in a storm category, ” he said, “We have made clear that in no way, shape, or form, that this is going to reduce the impact of flooding and increase.”

Shepherd, a former president of the American Meteorological Society, said the weather service did an amazing job at predicting and made a good attempt to communicate the risk. But in one way or another the message is not quite getting there, ” he said.

It didn’t for Wayne Mills. As the storm remained a Category 4, Mills said: “I would have to leave.”

Cutter and the Shepherd said: the weather should work with social scientists who research how people react and why. Laplenta said that his office does this regularly and will be doing more after Florence.

It’s only going to need more in the future because global warming is making hurricanes wetter and slower, so it falls more rain, and the Shepherd said.

University of Alabama, Jason Senkbeil studies the intersection of meteorology and the social sciences and is working on two different new hurricane scales using letters to describe a danger or potential damage. Florence is an “Rs” for rain and storm surge.

The trouble, said Senkbeil, “precipitation does not sound threatening.”

But Famous Roberts know now is: “I would say for everyone to observe. And don’t take anything for granted.”


Borenstein reported from Washington, Breed from North Carolina.


Follow Seth Borenstein on Twitter: @borenbears . His work can be found here .


The Associated Press Health & Science Department receives support from the Howard Hughes Medical Institute, Department of science Education. The AP is solely responsible for all content.


For the latest news on Hurricane Florence, visit .

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