<p>Well for one major reason, the assumption was that seasons with so numerous hurricanes were rare. Canonically, tropical cyclones typically follow a <a href="https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/JZ065i001p00213" rel="noreferrer">Poisson Distribution</a>. If you consider that, of the English alphabet, only 21 of 26 letters are used for names, and if you assume that the average number of hurricanes from the past decade were to stay unchanged compared to this decade <a href="https://en.wikipedia.org/wiki/Atlantic_hurricane_season#2010s" rel="noreferrer">(155 tropical storms/10 years= 15.5 tropical storms per year)</a>, then the probability of going over 21 tropical cyclones is about 6.96%. <a href="https://public.wmo.int/en/media/news/2020-hurricane-season-exhausts-regular-list-of-names" rel="noreferrer">Such a view is backed up by the World Meteorological Organization</a>.</p>
<p>But if you say, &quot;aren't the number of tropical cyclones supposed to increase under climate change?&quot; to challenge my assumption of constant tropical cyclones per decade, I will argue that canonically, <a href="https://www.noaa.gov/news/study-climate-change-has-been-influencing-where-tropical-cyclones-rage" rel="noreferrer">the frequency that tropical cyclones form should decrease, but the intensity should increase</a>. So the assumption doesn't actually hold, but should actually overestimate the probability of more hurricanes in the long term.</p>
<p>So why use Greek letters? Well, to be consistent, something has to be used to draw attention to the storm. Cycling back to the A's sends the wrong message. And <a href="https://www.fox23.com/news/science/2020-hurricane-season-could-use-greek-alphabet-only-second-time-ever/2K2GBUHGDRD2ZG5HEFW4P37DRM/" rel="noreferrer">the Greek alphabet was used previously, without major consequence</a>.</p>
<p>Arguably, it may be easier to only name storms that make hurricane strength. However, that would be inconsistent, and may miss strong, rain-heavy storms. For example, <a href="https://en.wikipedia.org/wiki/Tropical_Storm_Allison" rel="noreferrer">Tropical Storm Allison was retired without making the hurricane wind requirement</a>.</p>

CC BY-SA 4.0
2020-11-18T23:04:51.600Z
"But if you say..." you read my mind! :-)  But the main issue raised in the block quote is the problems associated with name retirement. If I understand correctly (and I"m not sure that I do) "Dabc" can retire and "Dxyz" can be used, so the letter "D" is still available, but if "Delta" is retired then the whole Greek letter "Δ" would have to be retired because they are letters, not words beginning with letters. Is it possible to address that as well? Was the retirement issue not considered at the time the Greek letter names were added? Was it not in place yet perhaps?
uhoh
CC BY-SA 4.0
2020-11-18T21:16:15.353Z
2020-11-18T21:16:15.353Z
BarocliniCplusplus
<p>The Washington Post article <a href="https://www.washingtonpost.com/weather/2020/11/17/greek-letter-hurricane-names-retire/" rel="nofollow noreferrer">Hurricanes Eta and Iota brought disaster to Central America. Officials can’t retire their names.</a> describes a complicated situation, aspects of which are:</p>
<blockquote>
<p>Eta roared ashore in northern Nicaragua on Nov. 3, followed by Iota exactly 13 days later and just 15 miles to the south. Both were Category 4 hurricanes at landfall, though Iota had attained Category 5 status offshore. The pair brought flood disasters across Central America, in addition to extreme wind and storm surge near the coast.</p>
<p>They’re the textbook candidates for having their names axed from the Hurricane Center’s six-year rotating name list. Just as Katrina was replaced by Katia, Michael with Milton, and Sandy with Sara, there would ordinarily be little question that the name of a deadly and destructive Category 4 hurricane would be retired. But in the case of the Greek alphabet, there’s no easy replacement.</p>
<p>“The Committee … agreed that it was not practical to ‘retire into hurricane history’ a letter in the Greek Alphabet,” read a news release from the World Meteorological Organization, which oversees hurricane naming across the world’s oceans.</p>
<p>Instead of removing a letter from the list, Greek letters can only be symbolically retired. Under the current policy, “Eta 2020” and “Iota 2020” would be listed as retired storms if the WMO voted accordingly, but the names Eta and Iota would remain in circulation for future storms. <strong>Some meteorologists fear this defeats the purpose of retiring names, while others find that assigning Greek letters to storms is impractical to begin with.</strong></p>
</blockquote>
<p><strong>Question:</strong> Why exactly were Greek letters used as names for Hurricanes in the first place, despite the fairly obvious and predictable impracticalities? Certainly this exact problem was brought up, how was it dismissed?</p>
<p>Related but different (because the current question is backward-looking), and also in need of answers:</p>
<ul>
<li><a href="https://earthscience.stackexchange.com/q/20222/6031">In the future, is the World Meteorological Organization going to allow Hurricanes Zeta, Eta, and Theta to exist simultaneously?</a></li>
<li><a href="https://earthscience.stackexchange.com/q/20224/6031">What will happen if the Greek letter names were exhausted for naming tropical storms?</a></li>
</ul>

CC BY-SA 4.0
2020-11-19T00:12:42.347Z
This is like asking why doesn't the US have a process set out for if no presidential candidate gets to 270 electoral votes and the state delegations were split 25 to 25 ... these things were setup as failsafes that weren't particularly expected to be used (see eventual Wimbledon rule change after Mahut-Isner).  Now that such troubles have arisen in TC naming, I expect they'll work something useful out when the season quiets down.   So many people so excited over something the second it turns up.
JeopardyTempest
CC BY-SA 4.0
2020-11-19T00:17:18.703Z
In the end, the whole idea of names and retiring them has issues, we're almost out of I names, and a few others like female Os. Often the same people itching for naming winter storms seem up in arms there wasn't a setup in place for retiring Greek names. Folks should chill. Worse comes to worst, maybe they just stop naming storms (wouldn't be the worst thing... it's not vital!). As Baroclinic suggests, maybe we stop naming tropical storms at least (since 15 is the record number of hurricanes), easy solution, & brings back storm #s into use (since TDs are now rare). We'll see, no stress.
JeopardyTempest
CC BY-SA 4.0
2020-11-19T00:20:35.070Z
@JeopardyTempest I think it would be great if you also posted much if not all of this as an additional answer rather than in comments only. It's exactly this kind of background that the question seeks. While I might be one of the "excited people" I'm mostly excited about the opportunities for answers to be added through the writing of a question.
uhoh
CC BY-SA 4.0
2020-11-19T00:30:23.360Z
Not sure my input merits a full answer... in the end it's just opinion, not something I have scientific references or deep logic to or such. Which is the point -- it's all rather insignificant to science in the grand scheme. Not complaining you\others asked, you're not the only ones clamoring on it (otherwise WP wouldn't have written the article)... but just saying you're asking for someone's motivation, which generally can only be hypothesized and opinions unless the few involved answer. Many SE sites close such questions. I'm not for doing so here, but I doubt you get many eyeopening answers
JeopardyTempest
CC BY-SA 4.0
2020-11-19T00:54:37.100Z
@JeopardyTempest okay got it, but I won't know what answers will be posted until I first ask and then the question stays open a while to find out. High question rate SE sites do the insta-closing with a triage mindset. In low question rate sites the community can simply keep an eye on a question and as long as it doesn't attract a zillion low quality answers per second, just wait to see if someone does have some specific sources or insight that others didn't already know about.
uhoh
CC BY-SA 4.0
2020-11-19T04:05:40.323Z
Why do you consider it impractical?  Just because the people who give names to hurricanes are silly enough to retire some of the names, doesn't mean they have to continure the practice with Greek letter names.  IOW, it's the irrationality of the naming committee that's the problem.
jamesqf
CC BY-SA 4.0
2020-11-19T08:18:33.487Z
Just a comment about @JeopardyTempest "maybe they just stop naming storms (wouldn't be the worst thing... it's not vital!)", here are some papers discussing the importance (or not) of naming storms for risk communication: https://doi.org/10.1175/WCAS-D-16-0037.1, https://doi.org/10.1002/met.1794, 
https://doi.org/10.1175/WCAS-D-18-0008.1
Jean-Marie Prival
CC BY-SA 4.0
2020-11-19T15:29:09.867Z
Quick thought: would retiring be workable? We're 9 of 24 through the Greek alphabet.  Even with 3 more storms this year, and if we retired Delta, Eta, and Iota, that'd still leave ~ 12 names the next time we had a record yr. If we go full conservative, believe weather unchanging, we only use the list every 35 years on average and retire 1.5 per use... 8*35=280 yrs of use left. If we instead use recent years to believe storms increasing, 15 year reuse, 8*15=120 yrs. Even if it ramped up more, and EPac needed them too (WPac\CPac don't have annual lists), Greek names seem to last a long time.
JeopardyTempest
<meteorology><tropical-cyclone>
Why exactly did the use of Greek letters as names for Hurricanes happen the first place, despite the fairly obvious and predictable impracticalities?
uhoh
# Why exactly did the use of Greek letters as names for Hurricanes happen the first place, despite the fairly obvious and predictable impracticalities?

(Asked by: username_0 on 2020-11-18)

The Washington Post article [Hurricanes Eta and Iota brought disaster to Central America. Officials can’t retire their names.](https://www.washingtonpost.com/weather/2020/11/17/greek-letter-hurricane-names-retire/) describes a complicated situation, aspects of which are:

> Eta roared ashore in northern Nicaragua on Nov. 3, followed by Iota exactly 13 days later and just 15 miles to the south. Both were Category 4 hurricanes at landfall, though Iota had attained Category 5 status offshore. The pair brought flood disasters across Central America, in addition to extreme wind and storm surge near the coast.
>
> They’re the textbook candidates for having their names axed from the Hurricane Center’s six-year rotating name list. Just as Katrina was replaced by Katia, Michael with Milton, and Sandy with Sara, there would ordinarily be little question that the name of a deadly and destructive Category 4 hurricane would be retired. But in the case of the Greek alphabet, there’s no easy replacement.
>
> “The Committee … agreed that it was not practical to ‘retire into hurricane history’ a letter in the Greek Alphabet,” read a news release from the World Meteorological Organization, which oversees hurricane naming across the world’s oceans.
>
> Instead of removing a letter from the list, Greek letters can only be symbolically retired. Under the current policy, “Eta 2020” and “Iota 2020” would be listed as retired storms if the WMO voted accordingly, but the names Eta and Iota would remain in circulation for future storms. **Some meteorologists fear this defeats the purpose of retiring names, while others find that assigning Greek letters to storms is impractical to begin with.**

**Question:** Why exactly were Greek letters used as names for Hurricanes in the first place, despite the fairly obvious and predictable impracticalities? Certainly this exact problem was brought up, how was it dismissed?

Related but different (because the current question is backward-looking), and also in need of answers:

* [In the future, is the World Meteorological Organization going to allow Hurricanes Zeta, Eta, and Theta to exist simultaneously?](https://earthscience.stackexchange.com/q/20222/6031)
* [What will happen if the Greek letter names were exhausted for naming tropical storms?](https://earthscience.stackexchange.com/q/20224/6031)

**Tags:** meteorology, tropical-cyclone

> **Comments:**
> **username_1**: This is like asking why doesn't the US have a process set out for if no presidential candidate gets to 270 electoral votes and the state delegations were split 25 to 25 ... these things were setup as failsafes that weren't particularly expected to be used (see eventual Wimbledon rule change after Mahut-Isner).  Now that such troubles have arisen in TC naming, I expect they'll work something useful out when the season quiets down.   So many people so excited over something the second it turns up.  
> **username_1**: In the end, the whole idea of names and retiring them has issues, we're almost out of I names, and a few others like female Os. Often the same people itching for naming winter storms seem up in arms there wasn't a setup in place for retiring Greek names. Folks should chill. Worse comes to worst, maybe they just stop naming storms (wouldn't be the worst thing... it's not vital!). As Baroclinic suggests, maybe we stop naming tropical storms at least (since 15 is the record number of hurricanes), easy solution, & brings back storm #s into use (since TDs are now rare). We'll see, no stress.  
> **username_0**: @username_1 I think it would be great if you also posted much if not all of this as an additional answer rather than in comments only. It's exactly this kind of background that the question seeks. While I might be one of the "excited people" I'm mostly excited about the opportunities for answers to be added through the writing of a question.  
> **username_1**: Not sure my input merits a full answer... in the end it's just opinion, not something I have scientific references or deep logic to or such. Which is the point -- it's all rather insignificant to science in the grand scheme. Not complaining you\others asked, you're not the only ones clamoring on it (otherwise WP wouldn't have written the article)... but just saying you're asking for someone's motivation, which generally can only be hypothesized and opinions unless the few involved answer. Many SE sites close such questions. I'm not for doing so here, but I doubt you get many eyeopening answers  
> **username_0**: @username_1 okay got it, but I won't know what answers will be posted until I first ask and then the question stays open a while to find out. High question rate SE sites do the insta-closing with a triage mindset. In low question rate sites the community can simply keep an eye on a question and as long as it doesn't attract a zillion low quality answers per second, just wait to see if someone does have some specific sources or insight that others didn't already know about.  
> **username_2**: Why do you consider it impractical?  Just because the people who give names to hurricanes are silly enough to retire some of the names, doesn't mean they have to continure the practice with Greek letter names.  IOW, it's the irrationality of the naming committee that's the problem.  
> **username_3**: Just a comment about @username_1 "maybe they just stop naming storms (wouldn't be the worst thing... it's not vital!)", here are some papers discussing the importance (or not) of naming storms for risk communication: https://doi.org/10.1175/WCAS-D-16-0037.1, https://doi.org/10.1002/met.1794,  https://doi.org/10.1175/WCAS-D-18-0008.1  
> **username_1**: Quick thought: would retiring be workable? We're 9 of 24 through the Greek alphabet.  Even with 3 more storms this year, and if we retired Delta, Eta, and Iota, that'd still leave ~ 12 names the next time we had a record yr. If we go full conservative, believe weather unchanging, we only use the list every 35 years on average and retire 1.5 per use... 8*35=280 yrs of use left. If we instead use recent years to believe storms increasing, 15 year reuse, 8*15=120 yrs. Even if it ramped up more, and EPac needed them too (WPac\CPac don't have annual lists), Greek names seem to last a long time.  

---

## 1 answers

### Answer by username_4 on 2020-11-18. Score: 5

Well for one major reason, the assumption was that seasons with so numerous hurricanes were rare. Canonically, tropical cyclones typically follow a [Poisson Distribution](https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/JZ065i001p00213). If you consider that, of the English alphabet, only 21 of 26 letters are used for names, and if you assume that the average number of hurricanes from the past decade were to stay unchanged compared to this decade [(155 tropical storms/10 years= 15.5 tropical storms per year)](https://en.wikipedia.org/wiki/Atlantic_hurricane_season#2010s), then the probability of going over 21 tropical cyclones is about 6.96%. [Such a view is backed up by the World Meteorological Organization](https://public.wmo.int/en/media/news/2020-hurricane-season-exhausts-regular-list-of-names).

But if you say, "aren't the number of tropical cyclones supposed to increase under climate change?" to challenge my assumption of constant tropical cyclones per decade, I will argue that canonically, [the frequency that tropical cyclones form should decrease, but the intensity should increase](https://www.noaa.gov/news/study-climate-change-has-been-influencing-where-tropical-cyclones-rage). So the assumption doesn't actually hold, but should actually overestimate the probability of more hurricanes in the long term.

So why use Greek letters? Well, to be consistent, something has to be used to draw attention to the storm. Cycling back to the A's sends the wrong message. And [the Greek alphabet was used previously, without major consequence](https://www.fox23.com/news/science/2020-hurricane-season-could-use-greek-alphabet-only-second-time-ever/2K2GBUHGDRD2ZG5HEFW4P37DRM/).

Arguably, it may be easier to only name storms that make hurricane strength. However, that would be inconsistent, and may miss strong, rain-heavy storms. For example, [Tropical Storm Allison was retired without making the hurricane wind requirement](https://en.wikipedia.org/wiki/Tropical_Storm_Allison).

> **Comments:**
> **username_0**: "But if you say..." you read my mind! :-)  But the main issue raised in the block quote is the problems associated with name retirement. If I understand correctly (and I"m not sure that I do) "Dabc" can retire and "Dxyz" can be used, so the letter "D" is still available, but if "Delta" is retired then the whole Greek letter "Δ" would have to be retired because they are letters, not words beginning with letters. Is it possible to address that as well? Was the retirement issue not considered at the time the Greek letter names were added? Was it not in place yet perhaps?  

---

