The way to name hurricanes will never be the same

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At the end of a virtual session operated from March 15 to 17, the World Meteorological Organization Hurricane Committee (OMM) announced a noticeable change in the naming of tropical systems in the future. Indeed, the previous procedure had weaknesses clearly identified during the exceptional 2020 season in the North Atlantic.

Tropical cyclones are named according to lists of names recurring every 6 years. Those of the North-East Atlantic and Pacific Basin are defined several years in advance by theWorld Meteorological Organization and apply as soon as a system reaches the tropical storm stage. They have 1 name per letter, with the exception of those poor in choice, which brings to a total of 21 per year. Usually the number of named disturbances is significantly less than this figure – the average being 12 per year.

However, it may happen that a greater number of phenomena occur during the same season. In this case, the procedure is to resort to the Greek alphabet: Alpha, Beta, Gamma, etc. A fact that has only happened twice in history, in the years 2005 and 2020 in the North Atlantic. 6 Greek letters were used for the first and 9 for the second. But such an event is no longer likely to happen. Indeed, the World Meteorological Organization Hurricane Committee has recently announced that the Greek alphabet would no longer be used.

Names used in the 2020 Atlantic season are crossed out. Credits: OMM / OMM.

Why such a decision ?

The Committee raises several points, including that ofan audience that focuses too much on the use of a Greek name and less on security messages or the dangerousness of the named system. In this regard, it has been observed that the appointment has sometimes been more discussed than the risks associated with the hurricane in question. And this, both in the media and on social networks. Also, since the Greek alphabet has many similar names, communication was degraded. For example, the coexistence of Eta, Theta and Iota in 2020 has led to some confusion.

Another complication associated with the use of this alphabet is thatno name could be removed. It is recalled that a cyclone which causes heavy human or material losses sees its name banned from future lists. However, in view of the damage caused by hurricanes Eta and Iota, it appeared necessary to recast the procedure. Eventually, the experts agreed to define a complementary list of names. This will now be used instead of the Greek alphabet if the first one runs out. It meets the same rules as the nominal list and overcomes the weaknesses mentioned above.

hurricanes
Satellite image of August 23, 2020 with Hurricane Marco in the top left and Tropical Storm Laura (future category 4 hurricane) in the bottom right. Credits: Wikimedia Commons.

The world of banned names

Let us conclude by recalling that the hurricane season of 2020 in the North Atlantic was exceptional in several respects. It is for example the one with greatest number of named systems (30). But it is also the only one marked by the occurrence of two major hurricanes in November. In other words, at the very end of the season. In total, theOMM will therefore have withdrawn 3 names used in 2020: Laura, Eta and Iota. They will be replaced by Leah for the 2026 roster and those from the secondary roster, respectively. Since hurricanes have been named, that is, since 1953, a total of 93 names have been banned from Atlantic lists. Among them, we find among others that of Katrina, still very present in our memories 16 years later.

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