We Shouldn’t Have Category 6 Hurricanes
Adding another level may do more harm than good
Hurricane Irma is going to be one of those storms that many of us remember for the rest of our lives. After the transformers blew, knocking out our power, my fiancee, cat, and I all huddled up in the bathroom and tried to sleep as the night skies opened with gales and rain. When we awoke the next morning (well, when I awoke; Steph doesn’t share my magical ability to sleep through almost anything), we learned that our apartment was now a waterfront property. A nearby lake had risen into the street running alongside our building. Once the wind died down a bit, we fired up the grill and started cooking foods for us and a couple friends of ours that would have otherwise gone bad in our dead freezers.
I got a lot of time in on that grill. We didn’t regain power for about 60 hours when it was all said and done. As bad as that sounds, we’re incredibly fortunate. As I write this, thousands of linemen from across the country, and even some from Canada, have come down to help restore power to the millions who have lost it and are otherwise suffering in the sweltering Florida heat. Some homes are flooded, others were flattened — the human and economic costs of this storm are immense. And even if many of us prepared, there can really be no truly adequate preparation for the damage that Irma has wrought.
At least we had the ability to prepare, though. Unlike some other storms, such as Katia that formed and hit Mexico in less than 48 hours, we had ample time to recognize and appreciate the threat of Irma. Forecasts from about a week out predicted a strong storm impacting the eastern United States and from 5 days out, we knew that it was going to hit Florida and that it was going to be strong. Very strong. It was announced that Irma was the strongest hurricane ever to be produced in the Atlantic basin. That it was going to impact the Caribbean as a category 5. That it may continue to intensify before swallowing the state of Florida — “swallow” not “impact” because it was about 400 miles across. It was a veritable super-storm, a tempestuous monster.
Unsurprisingly, there were ways that his awareness was a double-edged sword. There were a number of different memes, image macros, and blog posts warning that an ungodly, unheard of category 6 storm was barreling towards the Florida peninsula.
There’s a reason why such a storm would be unheard of: It can’t possibly exist. The Saffir-Simpson wind scale, which is what the National Hurricane Center uses to categorize wind-speed, only goes up to category 5 (defined as sustained winds above 157 miles per hour). But there have been very serious calls to extend the Saffir-Simpson scale to include a sixth category so as to capture the extreme damage potentials present in storms that are beyond being “solid” category 5's.
This isn’t the first time that such calls have been made; they echo similar sentiments made in the aftermath of Hurricane Katrina. Some people feel that the inclusion of a sixth category would allow people to better appreciate the threat that these storms bring.
I feel that this would be a terrible mistake.
I obviously don’t know very much about meteorology (and, fortunately, those who’s job it is to know about meteorology have shown no indication of adding that sixth level). But I do spend a lot of time thinking about how numbers and numerical scales influence people’s feelings and perceptions. And it just so happens that what little I do know about meteorology centers around hurricanes — both from living in the de facto hurricane capitol of the United States but also from a unique set of personal experiences in a specific niche of the construction industry focused on hurricanes.
My father was the owner and founder of Before the Wind Blows, a hurricane shutter company. If you installed hurricane shutters on your home in the central Florida and south Florida regions between 2004 and 2008 (and in a handful of reduced geographies from 2008 to 2014 — because, you know, the recession) there’s a better than even chance that my dad was responsible for your shutters. My brothers and I would spend decent amounts of our summers from about the time I was 12 onward helping out with small things around the warehouse. (Well, more accurately, my younger brother and I did the small things and my older brother was helping with the manufacturing). From about 16 to 19, I was helping my dad with summer installations. You get to talking to a lot of people when you’re heaving a few hundred pounds of aluminum around their house and conversations invariably circled around to hurricanes and the kind of protection these shutters would provide.
“These things will protect your windows from debris up to a category 3,” my father would say.
Then came the inevitable follow-up: “What about category 3 and above?”
“Anything above category 3, you’d probably be better off evacuating. They’re rated at cat 4 and 5 winds, but your walls aren’t. Your windows would be fine, but it’s kind of a moot point when your house has been blown to the ground.”
The point that my father was trying to deliver echos the purpose that the scale’s progenitor, Herbert Saffir, had for these categories. The cuts between one and two, two and three, etc, were based upon wind speed but were meant to deliver more qualitative information about the amount of damage that the storm was expected to bring. According to the National Hurricane Center, Category 1's signifies “very dangerous winds [that] will produce some damage.” Category 2's promises “extensive damage.’” Category 3's promises devastation. Categories 4 and 5 both promise “catastrophic damage.” The shutters would limit the wind-based damage on one’s windows and home up to the point of “devastation.” They couldn’t do much past the point of “catastrophic” because nothing can do much beyond the point of catastrophic.
There’s a tendency for people in hurricane prone areas to discount the intensity of category 1 and 2 storms. We know that the National Hurricane Center considers them “very dangerous,” but we’ve been through a number of them so we believe that we’ll be fine again. When I talked to people, if a weaker storm was on the horizon, they would often express a kind of flippant indifference mixed with the unique brand of Florida defiance best exemplified recently by the smattering of Facebook events advertising that participants spin their arms really fast or direct their expensive Disney mist fans in the same direction to divert Irma. But we also do so because, well, it’s only a one or two out of a possible five. The qualitative meanings that the categories represent have eroded leaving only the numerals. We have grown accustomed to thinking that these numerals are actually scientific numbers, precise measures of expected intensity arranged on a one to five scale of equally important intervals. Two is twice as large as one and half as large as four. Makes intuitive sense — even if it’s wrong. Like, wrong in all considerations. The amount of energy required to produce a category 5 is near-exponentially stronger than for a category 1. And even if you were only looking at wind speed, the winds of a category 5 storm are twice as strong as those in a category 1. Which should not make you lower the intensity of a 5 in your mind: It should cause you to raise the intensity of a 1.
Wrong or not, an important thing to do is to understand people’s cognitions as they actually happen and not as we’d ideally like them to happen. So let’s look at how the structuring of scales influences people’s perceptions of the phenomena they intend to represent and capture.
Research on survey measures has shown that people’s perceptions of the phenomenon in question are going to be anchored by both the range and highest number presented. When you present people with a five point scale, with one being the lowest and five being the highest, they will recognize one and five as being polar opposite “extremes.” They’ll apply their prototypes (the images they have in their minds based upon their experiences) of these extremes onto the significant numbers in the scale and interpolate the gaps as a function of the scale’s range and available intervals. (Basically, they’ll see a “1” as “not a huge deal,” “5” as “a very, very big deal” and shade in the remaining three in ways that depend on their familiarity with the subject matter). But it also means that people are going to ignore the gaps more and more as the scales start to get larger.
As you expand the scales, to seven and nine-point measures, evidence from survey research shows that attention starts to cluster around the poles and the mid-point. Expand them out too far, to things like 100 point scales, and people will still be anchored to “even” intervals (i.e., 10, 20, 30 — maybe 15, 65, 85, etc). The accepted reason is that respondents are giving answers that do not require much of a cognitive load; it’s easier to indicate the extremes and midpoint and, for those who don’t, it’s much easier to imagine things working on a number line ordered by the base 5/10 system that we’re so familiar with. But the result is that the impression delivered by the numbers within the gap are going to be increasingly subject to the range of the scale.
If one is the weakest and five is the strongest, then people are probably going to think that a category 2 is something to pay attention to but not take as seriously. But if they were to increase the end point to a six, to extend the range of the scale, then people start to feel that category 2’s are weaker than they were before. To illustrate, imagine that we weren’t extending the scale to six. Let’s imagine that we, for whatever reason, wanted our scale to include the sort of storms on Neptune. Accordingly, we are bringing in 95 new categories so that there’s now such a thing as a category 100 storm. As with the idea of a category 6, this isn’t shifting the scale so that a category 2 would now be seen as, say, a category 35. This is merely tacking on new divisions on top of the existing scale. If people were to know that but not clearly understand the qualities and context of a category 100 storm, how serious do you think people would start taking category 2 storms? If your answer is anything other than “not at all,” you severely overestimate people’s penchant to panic. And, to be crystal clear, a category 2 is absolutely something that one should take seriously. Remember how my house became a waterfront property? How other homes flooded? How we were lucky to be without power for only 2-and-a-half days? We only got Irma when she deteriorated to a category 2. Everything that our community has dealt with is a result of a storm that would not have been labeled as “major.” Diluting people’s perception of the storm can put lives at risk. And this sort of diluting is exactly what would happen if we were to add a sixth category.
To be clear, I don’t think that the discounting effects from including a sixth category would be anywhere near as large as it would be from including another 95. Nor, for that matter, would I expect that it would appear substantial on a percentage basis. I’d be surprised if this increased the number of people who would stay behind in a storm by half a percentage point, maybe one percent. It may be a small percentage but tens of millions of people are impacted by that small percentage. A percentage increase of half-of-one percent with a population of, say, 10 million, is still going to impact 50,000 people. That’s 50,000 people who otherwise would have evacuated, who otherwise would have been out of harm’s way.
The fact that categories 4 and 5 promises identical qualitative assessments of the aftermath (“catastrophic damage”) demonstrates that including a category 6 would be redundant at best — it would provide no new information for those who understand the qualitative weight of these measures as Saffir tried to instill and my father attempted to impress upon people.
But we don’t live in an “at best” world. Most people do not translate the numerals into descriptions; they only see the numbers. To add another category would be to extend the endpoint of the scale and, consequentially, diminish the significance that people place on storms that they should take seriously. Adding an extra category, in short, would be categorical mistake.
Peter R. Licari is a Graduate Student in Political Science at the University of Florida specializing in American Politics, Political Behavior, and Political Methodology. The opinions expressed are his own. He can also be found on YouTube and on Twitter. What little spare time remains is dedicated to long-distance running, video games with his ever-patient fiancee, and to oddly productive one-sided conversations with his cat, Asia.
