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If we learn only one thing from Hurricane Florence, it should be this: Don’t judge a hurricane by its category.
The heavy rainfall and flooding from Florence — and the 51 people left dead in its wake (40 in North Carolina) — have renewed debate about the wind speed-based classification system currently used for hurricanes.
Florence was forecast to make landfall as a Category 4 storm. People on the coast — and inland — took the storm seriously, evacuating and prepping for what promised to be the strongest hurricane to hit North Carolina in more than 50 years.
But as the storm moved closer to land, the wind speeds weakened and Florence was downgraded, eventually hitting Wrightsville Beach on Sept. 14 as a Category 1 hurricane. By the time it moved inland, it was a tropical storm, and many in its path breathed a sigh of relief.
Then came the floods.
Do we need to change the way we talk about hurricanes?
Chris Vaccaro, a spokesman for the National Oceanic and Atmospheric Association, the parent agency of the National Hurricane Center and National Weather Service, says the challenge with each and every storm is that each and every storm is different.
“Some of the most devastating storms in our nation’s history have been tropical storms or even tropical depressions,” Vaccaro told The News & Observer in a phone interview Tuesday as Hurricane Michael was threatening Florida and the Carolinas. “They move inland and lose their steering currents and just stall, as we saw with Harvey and as we saw with Florence … And so the challenge with each storm is communicating the various hazards from wind to storm surge to rainfall, and compounding that on top of the timeframe and the geographical location.
“It is a complex communications challenge,” he said.
Communicating the impact of storms
WRAL chief meteorologist Greg Fishel agrees that Hurricane Florence’s category rating alone — a system based on the Saffir-Simpson Hurricane Wind Scale — didn’t accurately reflect the danger of the storm. Fishel says meteorologists need to talk even more about the overall impact of storms, and he says the National Hurricane Center has been behind that.
“They’ve made some valiant efforts in the last few years to talk about impacts from things other than wind,” Fishel said in a phone interview. “They initiated the storm surge warnings, so that even if it was ‘only’ a Cat 1, there could still be a tremendous surge. So they tried to address that issue.
Fishel believes it will be more beneficial to expand the way storms are communicated, rather than eliminate the category system.
“If we were to eliminate (the category system) altogether there would be a shock factor,” Fishel said. “Maybe it would be a better idea to talk about what the impact of those winds are going to be, or maybe say something along these lines: With Hurricane Florence there are three different ways this could impact us. It could be wind speed, storm surge and flooding. What are the degrees of impact expected from each one of those three, what are the risk factors? And label them as minor, average, severe, whatever.
“I think the bottom line is people want to know how their life is going to be impacted, and in the case of Florence, yes, it didn’t make landfall as a Cat 4, but the size of the strong wind field — it was so large that the surge was still significant, so the impact was still significant and the category didn’t address that.”
Vaccaro says the tools to get forecasts to viewers are in place, and those tools are being used.
“There are separate forecast products for rainfall, such as flood watches and flood warnings,” Vaccaro said. “And we at the National Weather Service were communicating the dangers of Florence’s inland rainfall because we knew the storm would stall out. And it wasn’t just the National Weather Service, it was the entire weather community. The television meteorologists across the region and private sector companies were also echoing that same message in unison — that this is going to be a catastrophic flood event as well.”
No one perfect system
Wes Hohenstein, the chief meteorologist at CBS 17, is wary of talks about changing the current system. Changes mean educating everyone from meteorologists to viewers about the new system, and big changes can lead to more confusion, he said.
“I don’t know that changing it is a good idea, we just maybe need to do a better job as a state that has to deal with hurricanes in preparing for them and in understanding what our threats are,” Hohenstein said in a phone interview with The N&O. “I think everyone knows that it’s not just wind. It’s rain. On the coast, it’s storm surge. And it’s going to mean power outages. We know everything that comes with a hurricane.
“We also know that a Category 5 is bad and that a Category 1 is not as bad — but it’s still bad,” he said. “So I don’t know if changing things is a good way to make things easier to understand.”
Over at WTVD, those thoughts are echoed by chief meteorologist Chris Hohmann.
“The problem is, when it’s out in the ocean, the wind is the only thing to talk about,” Hohmann said. “You wouldn’t be able to use a different scale until it got to the coast.
“I think a new system, if you tried to incorporate all of the hazards and explain it — I don’t think anybody would understand it,” Hohmann said. “I think it would be too difficult to come up with something different. I think the thing is just to keep what we have and continue to try to verbalize that there are other threats besides wind and/or storm surge … Every hurricane is different and trying to come up with a scale that’s going to encompass all of the hazards of every storm would be too difficult and just too much for people to absorb.”
Another thing meteorologists aren’t likely to change is the weather graphic that shows the path of the storm — the fan, as it’s known.
Fishel said some people focus on the center line and assume that is the path of the storm and that meteorologists just add the fan to give themselves some wiggle room.
That’s not the point of the fan, he stressed.
“If you live in that fan you need to pretend like it’s coming straight for you,“ he said.
“And if it doesn’t, don’t be mad, be thankful. And if it does, you have given yourself the best opportunity to not only survive but perhaps minimize damage to your home and property.”
The science behind the fan is based on the average error of the National Hurricane Center’s forecast in the past, he said, which is not something most people want to get knee deep into.
“I was telling someone the other day, meteorologists don’t get into this field to live in Phoenix — they’re fascinated by the extremes and that’s why we get into it, but when you’re being victimized by one of these storms, you really don’t care about the science, you care about surviving. And so we have to sort of channel our energy from the fascination of the science to helping people get through it.”
Is this a social science problem?
Fishel thinks the emphasis on impact-based forecasting means we’re moving in the right direction, but will people pay attention?
“As long as we have a category scale that is based only on wind, I think we’re going to run into this problem where people say, ‘it was supposed to be a 4 and it’s only a 1 or only a 2, so I’m gonna ride that out.’ ”
Hohmann points out that North Carolina has been devastated by two Category 1 storms in two years, but no one talks about the Category 2 storm that hit the coast in 2014. Even though it was technically a stronger storm according to the Saffir-Simpson Scale, Hohmann said, it was a very different type of storm.
“Not that many years ago a hurricane hit — a Category 2, Hurricane Arthur — on the coast on the 4th of July, and it was in and out in a day or two and many people don’t even remember it because it was moving quickly,” he said.
The National Weather Service is aware of that disconnect, Vaccaro says, that many people may believe the category also reflects the potential storm surge and rainfall.
“We’re certainly mindful that some people do associate the category with overall intensity,” Vaccaro said. “And that’s a communication and social science issue that needs to be looked at more closely. If there are to be any changes made to the scale, there ought to be considerations as to what the implications of that are. I think this is kind of a complex social science issue that will kind of be looked at and researched in years to come.”
“That’s human nature,” he said. “That’s a sociology issue. We’re not going to find a system that’s immune to that. We can’t change human nature. I’m a meteorologist not a sociologist, but we’re going to have a tough time finding a perfect system. “