Hurricane rating system fails to account for deadly rain The Lumber River overflows onto a stretch Interstate 95 in Lumberton, N.C., Tuesday, Sept. 18, 2018, following flooding from Hurricane Florence. (AP Photo/Gerry Broome/AP Photo/Allen G. Breed)
Hurricane rating system fails to account for deadly rain
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Meteorologists downgraded Hurricane Florence from a powerful Category 4 storm to a Category 2. And then they downgraded it to a Category 1. That's when  Wayne Mills figured he could stick it out.

He regrets it. The Neuse River is normally 150 feet away, but it lapped near his door in New Bern, North Carolina, last Sunday. This was even as the storm had "weakened" further.

People like Mills can be lulled into thinking a hurricane is less dangerous when the rating of a storm is reduced. But those ratings are based on wind strength, not on rainfall or storm surge. Water is responsible for 90 percent of storm deaths.

Several meteorologists and disaster experts said something needs to change with the 47-year-old Saffir-Simpson Hurricane Wind Scale. They seek a change to reflect the real risks in hurricanes. They point to Florence. And they point to last year's Hurricane Harvey, 2012's Sandy and 2008's Ike. All were storms where the official Saffir-Simpson category didn't quite convey the danger because of its emphasis on wind.

"The concept of saying 'downgraded' or 'weakened should be forever banished." That's according to  Marshall Shepherd, a University of Georgia meteorology professor. "With Florence, I felt it was more dangerous after it was lowered to Category 2."

It was a lowered category that helped convince Famous Roberts, a corrections officer from Trenton, to stay behind. "Like a lot of people (we) didn't think it was actually going to be as bad," he said. "With the category drop ... that's another factor why we did stay."

Once a storm hits 74 mph it is considered a Category 1 hurricane. It ratchets up until it reaches the top-of-the-scale Category 5 at 157 mph (252 kph). Florence hit as a Category 1 with 90 mph winds — not a particularly blustery hurricane — but one that dumped nearly three feet of rain in parts of North Carolina and nearly two feet in sections of South Carolina.

"There's more to the story than the category," University of Miami hurricane researcher Brian McNoldy said. "While you may still have a roof on your house because 'it's only a Category 1,' you may also be desperately hoping to get rescued from that same roof because of the flooding."

Susan Cutter, director of the 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 beyond winds."

One reason, she said, is that it's much harder to explain all the other facts. Wind is easy.

The National Oceanic and Atmospheric Administration says it takes all hazards, including rain and storm surge seriously — and communicates them. 

Forecasters were telling people four or five days before Florence hit that it would be a "major flooding event," said Bill Lapenta, director of NOAA's National Centers for Environmental Prediction, which includes the hurricane center.

When Florence's winds weakened and it dropped in storm category, he said, "We made it very clear that in no way shape or form that this is going to reduce the impacts in terms of flooding and surge."

Shepherd, a former president of the American Meteorological Society, said the weather service did a great job at forecasting and made a good attempt at communicating the risk. But somehow the message isn't quite getting through, he said.

It didn't to Wayne Mills. If the storm stayed a Category 4, Mills said, "I definitely would have left."

Cutter and Shepherd said the weather service needs to work with social scientists who study how people react and why. Laplenta said his agency does that regularly and will do more after Florence.

It's only going to be more necessary in the future because global warming is making hurricanes wetter and slower. This makes them drop more rain, Shepherd said.

University of Alabama's Jason Senkbeil studies the intersection of meteorology and social science and is working on two different new hurricane scales using letters. They will describe danger or potential damage. Florence would be an "Rs" for rainfall and storm surge.

The trouble, said Senkbeil, is "rainfall just doesn't sound threatening."

But Famous Roberts now knows it is: "I would say for everybody to take heed. And don't take anything for granted."

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CRITICAL THINKING QUESTION
Why was rating system misleading?
Write your answers in the comments section below


COMMENTS (7)
  • JennaD-sto
    10/04/2018 - 11:36 a.m.

    The rating system is misleading because its based on wind and the wind does not make or brake how big the storm is. The rating should also have how much rain is coming and flood warnings.

  • MckenzieH-dec
    10/05/2018 - 10:13 a.m.

    This was so tragic!! ????????

  • azane-wim4
    10/12/2018 - 12:07 p.m.

    The rating system is misleading because it doesn't say how much rainfall or how much water flooded from the hurricane.

  • azane-wim4
    10/12/2018 - 12:08 p.m.

    the rating system is misleading because it doesnt say how much rain fall came in or how much water flooded from the hurricane.

  • mthor-wim5
    10/12/2018 - 12:57 p.m.

    I think this new system they are working on will help people understand the impact and how much damage the storm can do. SO now instead of rating the storm by number they will rate by letters. The letters will describe the danger and potential damage. This passage really helped me understand that even if the say the storm downgrade it is still very dangerous and deadly.

  • SummerS-dec
    10/18/2018 - 08:49 a.m.

    Crazy.. Wow

  • DavidD-lam
    10/26/2018 - 09:53 a.m.

    Now while I believe that the system used for categorizing storms works well. It does not work well enough to convey the message of how dangerous it is for people to be staying in the area. I agree that the weather should work more with social scientists to better convey the message of how dangerous it is to be staying in a hurricane. The categorical system used only accounts for wind speed when it really should account for both wind speed and amount of rainfall. I would throw my two cents into how the system should be made but I don't have enough experience in that field to say much on that.

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