Is it time to rethink hurricane categories?

ROB SCHMITZ, MODERATOR:

Within two weeks, two hurricanes, Helene and Milton, struck the southeastern United States. Both storms were classified as major hurricanes, meaning Category 3 or higher. And those categories, known as the Saffir-Simpson scale, likely saved many lives by warning about the storm’s potential dangers, but some say that scale is inadequate. Alec Luhn is a climate journalist who reported on this. He says the scale takes wind speed into account but misses a key danger.

ALEC LUHN: Hurricanes bring more water our way, and water is actually the real killer when it comes to hurricanes, not wind speed. Therefore, more and more meteorologists are calling for a different way of categorizing and quantifying a hurricane’s destructive power, as these larger, wetter hurricanes dump a lot of rain and cause a large storm surge, which is masses of seawater rising onto the coast or generated in some cases, such as Hurricane Milton, many tornadoes surrounding the hurricane, far from the eye of the storm.

SCHMITZ: That’s interesting. You know, you mentioned water as an additional threat besides wind. You know, is there a consensus about what scientists should include, like water, in an updated hurricane scale?

LUHN: The great strength of the Saffir-Simpson scale is that it is so simple and impressive. You hear Category 5 – 5 out of 5 – you know it’s going to be big. It sounds big…

SCHMITZ: Right.

LUHN: …And bad, and that’s the great thing about it. You don’t need to know much about hurricanes to really understand this. So how can we keep that simplicity and communicate it to people so easily, but also maybe give them a better sense of the destructiveness? One idea is to categorize hurricanes in the same way, categories 1 to 5, but based on sea level pressure rather than wind speed, since a hurricane forms in a low pressure area. The lower the pressure, the stronger the storm. And that has an advantage over wind speed because it would also bring together other types of storms that are destructive despite lower wind speeds, right? In other words, this scale could increase the number of the hurricane that was slower but still had greater force, putting it on the same level as a small, dense hurricane with high wind speeds. So one idea is to base it on sea level pressure.

There’s also the idea of ​​creating a category system based on precipitation, categories 1 through 5, based on how likely the precipitation is to be many times deadlier than you’re used to. In other words, a Category 3 would mean three times as much rainfall as would be expected in an area over a five-year period.

In short, there are many ideas on how to do this. But so far it’s been difficult to switch because Americans all know this Saffir-Simpson scale. Everyone knows hurricane categories 1 to 5.

SCHMITZ: You know, that raises a bigger question about climate change as well. You know, we know that warmer oceans make storms more intense and wetter. What do you think is the likelihood that we will see a different warning system as we experience more intense hurricanes due to climate change?

LUHN: I don’t think it’s very likely that we will deviate from the Saffir-Simpson scale in the foreseeable future. Although all meteorologists can point out its shortcomings, it conveys dangers to people even if they know little about hurricanes. What I think some people are saying is that we need to try to educate the public and get them to think beyond just scale and think about the impacts of hurricanes and the local impacts of hurricanes – right? – because if you live in a low lying area near the coast, a storm surge could be very, very deadly to you, much more deadly than wind speed or rain. If you live in an inland area that doesn’t typically rain that much or doesn’t have a good drainage system, you may be at risk of extreme rainfall. What impacts could a hurricane have on your community that could make it deadly?

SCHMITZ: This is Alec Luhn. He is a climate journalist and you can read his reporting on the Saffir-Simpson scale in WIRED magazine. Alec, thank you.

LUHN: Thank you. I’m pleased. Transcript provided by NPR, Copyright NPR.