Hey everybody, welcome back to Explain Backup 5. Podcasts always take questions you always wanted to ask and talk about them in a way that's easy to understand. We are your hosts, I'm Tim. Hey everyone, I'm Kevin.
So Kevin, today we're talking about hurricanes, and this topic is courtesy of a question we got from Fez and Seth in California, who asked us to do an episode on the weather. So the first question is, what is the difference between a hurricane, typhoon, and cyclone? Well, that's a really good question. They sound like different things, but they're actually all basically the same thing.
But they are given different names depending on where they appear. So, hurricanes are tropical storms that form over the North Atlantic Ocean and North East Pacific, while cyclones are formed over the South Pacific and Indian Ocean, and finally typhoons are formed over the Northwest Pacific Ocean. Hurricanes never seem to hit the West Coast of the U.S. Why is that?
Oh, well that's because the Pacific and Atlantic Oceans have currents that circulate in clockwise motions. So on the West Coast of the Oceans, it brings all this warm water up the East Coast from all, you know, further South, and passes by the Arctic Ocean up North, and then finally brings the cold water down the East side of the ocean. So that's why the West Coast of the U.S. gets cold water.
It's all coming from the Arctic, and the East Coast gets all that warm water from the Southern waters. It's also why the warm water is more likely to breed large storms. So that's why there's similarly lots of storms in Southeast Asia, basically just like the East Coast of the United States. Ah, and that's why there are no hurricanes in Europe, are they?
Yes, exactly. Another way to put it is that hurricanes in the Northern Hemisphere, they generally travel East to West. So for the same reason that California also doesn't get them as it has a bunch of land blocking the Eastern direction, so does Europe. But it can happen, it's just more rare.
So for example, they have only recorded one South Atlantic hurricane in all of history, and these are rare because of these clockwise motions again in the Pacific Atlantic that I just mentioned. So you're talking about water currents and the warm water coming up from the equator and the cold water coming down from the Arctic, but there's also the direction in which a hurricane spins. In the Northern Hemisphere, they spin counterclockwise, and in the Southern Hemisphere, they spin clockwise. And I'm curious if you could explain why is this.
So it's due in part to the rotation of the Earth, actually. It's called the Coriolis effect. Ah, Coriolis. Now that's the term we need to, Eli 5, explain.
Okay, okay, let me try. So the Coriolis effect is a force that is found in a rotating object. A French mathematician, Jaspard Gustave de Coriolis, first described the Coriolis effect in 1835. So to explain like I'm 5 here, let's pretend you're standing at the North Pole, okay?
Okay. And you throw the ball to your friend in the United States. It will appear to land to the right of him because of the fact that the Earth is spinning counterclockwise. Now, everywhere you play this game of global scale catch in the Northern Hemisphere, the ball will basically always deflect to the right.
So that's why the Coriolis effect means that, you know, for hurricanes in the Northern Hemisphere, they spin counterclockwise, and in the Southern Hemisphere, they spin clockwise. Oh, now is this why they say water flushes down a toilet or down a drain in opposite directions in the Northern Hemisphere? Oh, that's actually one of the opposite examples of the Coriolis effect. But sadly, it's likely not the case, actually.
In reality, the force of the Coriolis effect is not strong enough to see in such a small amount of water. But that has really stopped folks from perpetuating that myth. Apparently, there is an African country near the equator where entrepreneurs have set up two toilets, one just north of the equator and the other just south of it. And for a fee, they will allegedly demonstrate that the toilet is flush in opposite directions.
But, you know, it is only for show. There is no real effect. The Coriolis effect is really only affected for really large scale effects like hurricanes we've been talking about. Okay, now back to hurricanes.
How fast do they get? Very fast. The fastest wind ever recorded was 253 miles per hour. It was from tropical cyclone Olivia in 1996.
Oh, yes, Olivia. That was a long time ago. How fast does a cyclone or hurricane need to get before it gets a name? Oh, I really like how you asked about when they get named.
Because the answer is they are named once they have steady winds of 62 kilometers per hour or 39 miles per hour. Basically, that's important because that's the speed where the classification goes from something called a tropical depression to a tropical storm. And so these tropical storms have names. And actually, there's another level of classification above that where they finally reach that hurricane or typhoon or cyclone status, which is at 74 miles per hour or 118 kilometers per hour.
Got it. So the progression goes from tropical depression to tropical storm and then to hurricane. And the last two categories have storm names. Now, the next question is, why do we tend to get female names for hurricanes?
Oh, they are now male and female names. But there is a fascinating backstory to all of it. In fact, in history, tropical storms used to be named after saints for hundreds of years. The names really helped in forecasting, locating, and reporting.
But from 1887, it changed. So the first person to name storms was an Australian meteorologist named Clement Raggett. And he actually named not just hurricanes, but ordinary weather events too. And he would name them using names from the letters of the Greek alphabet and Greek and Roman mythology and also female names.
But then, sadly, the Australian government failed to really create a natural weather service with him as a director. So Raggett started naming them after the male politicians that he disliked. You know, that continued until he retired and his system stopped being used. So is that why then in the early 1900s we don't really have any cyclone or hurricane names?
Yes. If you look at history, there is a gap. So what happened is they stopped with Raggett's system of naming until it was revived in the latter part of the Second World War. And what happened was an author in 1941 was so inspired by reading about Raggett that wrote a novel called Storm about a fictional California storm which he named Maria, which then inspired a popular song they called the Wid Maria Mariah, in a probably musical Peter Wagon.
And lots of military meteorologists read the novel and during World War II, some of them started naming hurricanes and tropical storms in the Pacific after their wives and girlfriends. I see. So it's after the 1950s onwards where we have female names. And then until when did that last?
So that was until 1978 when both male and female names started being used for Pacific storms. And the system has now been formalized and rules were set up to make sure the names were alphabetical and culturally diverse. Did you learn something new? If you did, and especially if you are a regular listener of the live five, please keep us rating on iTunes.
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