The Complicated Art and Science of Naming Tropical Storms and Hurricanes

© Ugur Akinci
I never thought naming hurricanes was a complicated business. I originally thought Atlantic storms were given male names and Pacific storms female ones. Period. Boy, was I wrong. Nothing is that simple in life, is it?
My naïveté starts with the assumption that these are all “storms.” Nope.
It’s a “tropical storm” if the winds blow over 39 miles per hour. Until that threshold is reached, no wind deserves the title “tropical storm.” Makes sense, except: do these storms always blow around the tropics? Like, what if there’s one that’s chewing up Northern Scotland, or offshore Greenland? Do we still call it a “tropical” storm?

800px-Cyclone_Catarina_from_the_ISS_on_March_26_2004

Cyclone Catarina


And: what if the winds start blowing harder than 39 mph? That’s easy. If it’s over 74 mph it becomes a “hurricane” and please don’t ask me why at that exact speed. It’s the way U.S. National Weather Service decided.
Okay, what about a “cyclone”? What’s that? Oddly enough, the U.S. National Hurricane Center web site does not post a list of hurricane names but “cyclone names.”
Wikipedia basically says there’s no difference between a cyclone and a hurricane, and provides this fascinating factoid: the cyclones whirl clockwise in the Southern Hemisphere but counter-clockwise in the Northern Hemisphere. Did you know that? I sure didn’t.
Back to naming cyclones, or hurricanes…
There are many different ways to name a hurricane depending on the geography. Two major naming conventions define the Atlantic and Pacific storms.
Years ago, these storms used to be named after the latitude and longitude that they originated from. But there were two problems with that: people had difficulty remembering the exact name and thus mistakes were made in exchanging crucial information about storms with difficult-to-remember names.
Secondly, no storm stayed put (duh!). They started from point A, then went to B and C and so on. Thus naming a moving object by its stationary origination point didn’t make much sense either.
During WW2 American meteorologists started to use female names for storms in the Pacific. The convention was adopted in 1953 for Atlantic storms as well. The practice helped perk up the general public’s interest in hurricanes but didn’t sit well with feminists (and I consider myself one). To balance the scales, male names were introduced to designate the Eastern North Pacific storms, followed by adopting the same practice for Atlantic hurricanes in 1979.
300px-Hurricane_Isabel_from_ISS

Hurricane Isabel


Today, the U.S. National Hurricane Center uses a jaw-dropping list of 21 alternating male and female names for each year for Atlantic storms. Once in every 6 years the list rotates and we go back to the first list.
The storms are named starting with letter A (“Alex” for this year, for example), going down the alphabetical list.
For example, as these lines are written we are talking about hurricane “Earl” because the very last one was “Danielle.” That’s how the male and female names alternate for the Atlantic storms.
And what if there are more than 21 hurricanes in any given year? Greek alphabet to the rescue: storms are named “Alpha,” “Beta,” “Gamma,” etc.
See the list here http://geology.com/hurricanes/hurricane-names.shtml
Names of disasters like Katrina are “retired” from the list. I understand why that’s the case.
But there’s also a counter argument: if an approaching storm is expected to be as devastating as Katrina was, wouldn’t it make sense to call the new storm “Katrina” as well so that people would understand the severity of the situation and take appropriate measures right away? Other wise, we have to remind the public that “hurricane Bob will be as severe as Katrina.” There wouldn’t be need for that qualifier if names like “Katrina” were used for special cases rather than retired.
Anyway… “what about the Pacific storms, or the storms in other parts of the world?” you may ask.
That’s where things get even more complicated.
First off, there is no single list for the whole Pacific but 3 different ones for Eastern Pacific, Central Pacific, and Western Pacific.
Eastern Pacific names are just like Atlantic names: 21 names per year, rotate once every 6 years.
But Central Pacific has 4 shorter lists that are used sequentially. When you reach the end of the 4th list you revert back to the first name on List 1. Simple as that. There aren’t that many storms in the Central Pacific, I suppose…
Western Pacific is different in a “democratic” way. Yes, there are 5 lists with 28 names on each. These lists are used sequentially. But each row of this table is contributed by a different country with shore on or close to the Pacific. That way every year each nation has the dubious distinction of having contributed to the terminology by naming a disaster – provided, of course, there are at least 28 storms in any given year. If for example there are only 27 storms, no Vietnamese name is used that year for a Western Pacific storm. Or if there are 29 storms, a Cambodian name is used twice, etc.
Then there are those special storm naming systems used for Australia, Fiji, Papua New Guinea, Philippines, Northern Indian Ocean and Southern Indian Ocean…
I don’t believe there is a separate terminology for any Persian Gulf or Mediterranean hurricanes perhaps because no hurricanes ever hit those bodies of water.
If you’d like to learn more about those region-specific naming conventions you can visit these two very informative web sites:
http://www.nhc.noaa.gov/aboutnames.shtml
http://geology.com/hurricanes/hurricane-names.shtml
Now you know what’s in a name, don’t you?
As to your humble investigator, I’m still trying to find out how they name those fantastic polar cyclones…
What do you think about this post? Did you like it? Did we miss anything? How can we improve it to help you better? Please feel free to share your mind.
(Images courtesy of Wikipedia.)

2 Comments

  1. Professorcool on September 11, 2010 at 9:56 am

    The rotation of a tropical storm, tornado, or the watter running down a drain is caused by the “Coriolis Effect”, named for a French Scientist named Coriolis. The previously unnamed phenomenon was well known to military ordnace experts, who had long noticed that, in the Norhern latitudes, a cannon shot in a northerly direction seemed to curve to the right, whereas one to the south curved left. Shots directly east or west appeared unaffected.
    The effect is somewhat difficult to express simply in words, but here goes: Note that, due to the rotation of the earth, points on the surface are constantly moving to the East, at significant velocities. Because the curmference of the equator is approximately 25,000 miies, and the earth rotates once every 24 hours, the rotational velocity of a person standing at the equator is roughly 1,000 miles per hour in an easterly direction.
    At the north pole (the true, not magnetic pole), by contrast, the easterly velocity is zero.
    Therefore, it should be obvious that as one moves from south to north in the northern hemisphere.
    Now imagine a cannon sitting at the equator, that fires a cannonball directly north. Regardless of the northerly component of its velocity, it will have the easterly component of 1,000 miles per hour. As the cannon ball leaves the cannon, the earth below it has the same easterly velocity, so there is no apparent movement of the projectile to the east RELATIVE TO THE GROUND. However, as the projectile moves to the north, the easterly velocity of the ground will slow, but that of the projectile stays at 1,000 miles per hour (neglecting air friction, of course) the easterly velocity of the projectile becoomes greater than that of the earth, and the pojectile moves more rapidly east than the ground beneath. This creates the appearance of the “curve” to the right. A cannonball shot directly south would end up moving more slowly than the earth, and would appear to curve to the right.
    Now imagine a “bubble” of warm air forming over a warm portion of the ocean. As the bubble starts to rise through the atmosphere, cooler air rushes in at sea level to replace it. A molecule of air moving north will curve to the right, one coming in from the north (i.e. moving south), will curve to the right. If you draw this situation on a piect of paper, it will be obvious that this starts forces that begin a counter-clockwise rotation of the air around the center point of the rising column of air. As cooler air rushes in, it gains heat fromt the ocean and begins to rotate in turn. The process gains strength from the heat energy in the ocean water, and a rotating air mass is created. We call it a hurricane.



    • admin on September 11, 2010 at 10:15 am

      Wow! Amazing… Never heard of Coriolis Effect before. Thank you very much for your seminal contribution and the way you clearly and patiently explained different rotational velocities and the kind of difference they make for the cannonballs and the clouds. I learned something new and fascinating today. Ugur