Rachel Feltman: Happy Monday, listeners! For Scientific American's Science fast I'm Rachel Feltman. Today we'll mainly focus on one important story from last week: Hurricane Melissa.
Here to tell us more about this historic storm, Scientific American senior editor Andrea Thompson.
Andrea, welcome back to the show. Thanks so much for coming to talk about this.
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Andrea Thompson: Thank you for having me.
Feltman: So what is it about Hurricane Melissa that makes it such a historic and unusual storm?
Thompson: Where to start? Every meteorologist I've seen discussing this or talking to has just been somewhat alarmed by almost every aspect of this storm.
So, in any case, the presence of a category 5 in the Atlantic Ocean is quite rare. I think there have been about 45 since records began around 1851. And so the fact that you reach this rare territory is significant. It was the third Category 5 hurricane this hurricane season. And we've only had one season that had more than two Category 5 storms, and that was the really blockbuster season in 2005 that had Katrina and Rita, and that season actually had four Category 5 storms.
So the company you're talking about already exists – and it wasn't just Category 5; it reached the kind of intensity and peak wind speeds that we typically talk about more when we talk about super typhoons in the Western Pacific. And it's a region that may just be able to withstand larger, stronger storms than the Atlantic Ocean usually can. And so Melissa had peak wind speeds of 185 miles per hour, which is just astounding. Category 5, the standard for it is 157 mph, that's how much higher it was. [laughs].
It was just a perfectly symmetrical storm. It's kind of a textbook hurricane. And it reached that level very close to land while it was interacting – you know, some of its outer rain bands were interacting with Jamaica, and that tended to cause friction with the hurricane. And it's like, as one meteorologist told me, it's like Jamaica wasn't even there. It's like he didn't even notice that this island existed.
And the Category 5 storm persisted for more than 24 hours, which is remarkable—not only did it remain, but it continued to intensify. Typically, when storms get to this really high intensity, they go through some sort of internal process that can cause them to weaken for a short time, but get stronger, and then they may have time to intensify again.
Feltman: Certainly.
Thompson: Melissa never did this. It's just…
Feltman: Yeah.
Thompson: Left…
Feltman: And landfall should also slow them down.
Thompson: Yeah, and, you know, I think given how great Melissa was at landfall, Jamaica is relatively small compared to the hurricane. You know, it weakened him; I think on the other side it was only a category 3. But for it to go through the interaction with the ground and still be that strong, it's just…
Feltman: Right.
Thompson: Yes, it's stunning [laughs].
Feltman: Yeah, well, I feel like, you know, part of the surprise level, at least to the general public, is that this hurricane season seems to be relatively cold compared to the ones we've had lately. Would you say this is true?
Thompson: Yes, and part of that is because there haven't been many storms affecting the United States. They either formed and remained at sea or affected much of the Caribbean. And so we tend to, especially in the US, not notice it as much.
And we had that – we hovered around the average in terms of the total energy that hurricane season is expected to produce. But there were slightly fewer of us than predicted for this year. We expected this to be an active storm season.
Feltman: Yeah, well, and it's not like, you know, you mentioned it was 2005…
Thompson: Mm-hmm.
Feltman: Where it was one thing after another: “This is a really busy season.” It was just everything at once [laughs].
Thompson: [Laughs.] Yes. Yes, and we've had a couple of other pretty bad storms this year. But it is one of the six strongest storms in terms of maximum wind speeds, so only five other storms we know of have ever reached those wind speeds or higher.
Feltman: Wow.
Thompson: And it ranks third in terms of central pressure, so it dropped to 892 millibars. Anything below 900 millibars is a really strong hurricane, and that's not unusual for Atlantic storms given that sea level pressure is around 1,000 millibars. So just to give some perspective.
Feltman: Yeah, well, and, you know, I think with a real hard storm, the question is always, is this just one of those things that we call a once-in-a-century event, or is this something that we can expect more of?
Thompson: Yes, and so something like this would be relatively rare – like this level in the Atlantic. It probably won't be as rare as it used to be. There are clear signs that storms are generally stronger than in the past.
So when you think about the category 1 through 5 designations, we have more storms reaching those 3, 4 or 5 designations than we have in the past, so it's kind of a shift in that distribution from weaker storms to stronger ones. You know, a Category 1 storm is more effective now than it would have been in the past because it's going to be a little stronger – it has more energy overall to get out of the ocean. Sea levels are rising, so any storm surge will be higher than it has been in the past. The atmosphere could hold a little more moisture, so when it rains and there are heavy rainfalls, there is more moisture left to turn into rain, so you get heavier downpours than you might have had in the past.
Feltman: And what impact did Melissa have on Jamaica?
Thompson: So, as of the afternoon of October 30th, I think this is still becoming clearer. This has clearly devastated communities. You know, there are territories that have been more or less erased from the map. You can see footage of, you know, roofs being ripped off houses. It will take time to catalog all of this.
Several deaths have been reported in Jamaica and Haiti. They will almost certainly grow in the next few days because sometimes it takes a long time to get this information. Right now the death toll in Haiti is higher than in Jamaica, and I think they've been forgotten a little bit because Jamaica understandably took the brunt of it, so that's where the focus was. But Melissa also brought really heavy and huge rains to Haiti, and that could lead to huge landslides. Haiti's topography, the fact that it is severely treeless, means that rain of all kinds is concentrated and flows downwards, so landslides can occur; you may get a flash flood. This definitely happened in Jamaica.
As one meteorologist told me, you know, a storm like this leaves permanent scars on the landscape. You know, it's something that forever changes the land it hits.
Feltman: Thank you very much for coming and letting us know about this update.
Thompson: Glad to be here.
Feltman: You can read more about Hurricane Melissa on the website scientificamerican.com.
We'll wrap up with a quick look at other important science stories you may have missed. Meta-analysis of existing studies published last Wednesday in Journal of the American Heart Association found that certain viral infections can significantly increase the risk of cardiovascular disease. You've probably seen some Previous studies have linked COVID to long-term increases in heart attacks and strokes. But this new review, which analyzed 155 studies, found that other viral infections can also lead to these problems, including HIV, hepatitis C, shingles and even influenza. Although some viruses directly attack the heart muscleothers may indirectly cause cardiovascular problems by increasing inflammation. The authors of the new study noted that vaccination is the best way to prevent many of these viral infections, meaning that keeping up with your vaccinations may also help protect our heart health.
In space news, scientists using the global LIGO-Virgo-KAGRA network recently discovered two unusual black hole falls. Researchers described these cosmic collisions last Tuesday in That Letters in an astrophysical journal. According to the study, the party involved in one of the collisions turned out to be one of the fastest spinning black holes ever observed. In another crash, the black hole was spinning in the opposite direction of its orbit, which researchers say is a first. Both used pairs of black holes, one of which was much more massive than the other. Researchers say these characteristics may indicate that the objects are “second generation” black holes. This would mean they likely formed through a process called hierarchical merger, where black holes collide and merge repeatedly in densely populated areas of space such as star clusters.
Finally, here's some animal news to ponder. In a study published last Thursday in Science researchers report that chimpanzees can think like humans, or at least like us when we're on our best behavior. The researchers allowed the chimpanzees to guess which of two boxes might contain food. When they were first given a clue pointing to one box and later given a second, better clue indicating another contained a payload, they often changed their choice. The researchers say these results suggest that chimpanzees can think rationally, revising their beliefs by weighing the strength of new evidence presented to them. The team's next step is to compare how chimpanzees' rationality stacks up against similar experiments on humans between the ages of two and four. No word on when the researchers plan to pit these sentient apes against random adults on the internet, who we all know fail this test quite often.
That's all for this week's news. Tune in to Wednesday to learn why we have learned to sometimes remain silent when we know we should stand up to injustice, and how we can overcome our instincts and show defiance when necessary.
Science fast I am producing, Rachel Feltman, along with Fonda Mwangi and Jeff DelViccio. This episode was edited by Alex Sugiura. Shayna Posses and Aaron Shattuck check the facts on our show. Our theme song was composed by Dominic Smith. Subscribe to Scientific American for more relevant and in-depth science news.
For Scientific American This is Rachel Feltman. Have a great week!
