By Carolina Barnez Gramcianinov
Illustration by Silvia Gonsales
The 2017 Atlantic tropical cyclone season began on April 19, and by October, the Atlantic had seen 6 major hurricanes including Harvey, Maria, and Irma, which all went down in history. Irma was a devastating Category 5 hurricane, and we probably won't have any more hurricanes with that name in the Atlantic. Do you know why? Have you ever wondered where hurricane names come from and why we name them?
Naming tropical cyclones (also called hurricanes in the North Atlantic and East/Central North Pacific, or typhoons in the Northwest Pacific) with short, simple, first names makes communication and warnings to the population easier. In the past, codes involving latitude and longitude were used, but this caused some confusion due to the amount of letters and numbers. During the hurricane season, it is common to have more than one system active in the Atlantic at once, and it is important that the alerts are clearly understood for each of them. Confusion between hurricanes that occur at the same time in different regions or in sequence with one another was very common when the news was transmitted, mainly via radio, which delayed and compromised public announcements and evacuation plans.
Animation with satellite imagery from September 14, 2017 of the western North Pacific, with tropical cyclones Talim (farther north) and Doksuri (farther south). This color infrared image shows the characteristics of clouds, and consequently rain, associated with the atmospheric systems. The colder the cloud, the higher it is and the greater the potential for heavy rain. In the color scale, higher clouds are represented by the color red.
The tradition of naming hurricanes originated in the West Indies, where affected communities named them after the saint whose holiday was closest in occurrence. In the early 19th century, an Australian meteorologist started giving female names to cyclones, and this practice was adopted around the world, especially by Navy and Army meteorologists during World War II. It was not until 1978 that male names began to be used in the eastern North Pacific, and a year later in the Atlantic and Gulf of Mexico.
Currently, the names are chosen from lists organized by the World Meteorological Organization (WMO1). There is a series of lists for each oceanic region affected by tropical cyclones, making a total of 10 regional lists. They are all in alphabetical order, so it is easy to identify the cyclone number for that season. In any region, a tropical cyclone that starts with A is the first of the season. Regions with a lot of cyclone activity have longer lists. The Atlantic and Gulf of Mexico list, for example, has 21 names per season, the North Central Pacific has only 12. But what if during the season there are more hurricanes than names? Each region has a contingency plan for this. In the Atlantic the Greek alphabet was used, until confusion in 2020 led to changing to a backup list of names. The Greek alphabet had only been needed twice in busy hurricane seasons, once in 2005, the year of Hurricanes Katrina and Wilma, and again in 2020, which saw 9 Greek alphabet named storms. Due to a lack of understanding of the Greek alphabet, it was determined this system caused too much confusion and the WMO decided to use a backup list in the future, as is done in other regions.
GOES satellite images of Hurricane Wilma (2005) hitting Florida (USA). This was the most intense tropical cyclone recorded in the Atlantic basin, reaching winds of 295 km/h.
(Source: NOAA -https://www.ssd.noaa.gov/PS/TROP/trop-atl.html)
Each major region has a list that includes names for more than one year. When you get to the last name on the last available list, you go back to the first list. For example, in the Atlantic we have 6 lists, that means that every 7 years we repeat them. So in 2023 we will be using the same list as 2017. So sometimes we hear repeated names, or when we do research on a hurricane there will be more than one with the same name. But then there is the question: why don't names of "famous" cyclones like Katrina and Sandy appear on the list anymore? The answer is that, out of consideration for the victims, cyclones that have caused severe damage and many deaths have their names removed from the lists. When this happens, the WMO chooses a name with the same initial to replace it. This is the case with tropical cyclones Haiyan (Philippines, 2013), Sandy (USA, 2012), Katrina (USA, 2005), and Mitch (Honduras, 1998), for example. For more retired hurricane names, click here.
Hurricane Irma (2017) was among one of the most intense in history and was the most intense cyclone to hit the US since Katrina (2005). Another striking characteristic was the number of days at sustained maximum intensity: it maintained winds reaching almost 300 km/h for almost 2 full days. The damage was wide-spread and devastating, resulting in the removal of the name from the list. Irma was the eleventh name with an "I" to be removed from the Atlantic list, this initial being the one with the most names removed: Ione (1955), Inez (1966), Iris (2001), Isidore (2002), Isabel (2003), Ivan (2004), Ike (2008), Igor (2010), Irene (2011), Ingrid (2013). After the retirement of Irma in 2017, two more “I” names have further been retired, Iota (2020) and Ida (2021).
Example of the monitoring conducted by the US National Hurricane Center (NHC). In the image we can see Hurricane Jose and two disturbances with a small potential for cyclone development marked with yellow "X" (chances less than 40%).
If you want to know the names of future tropical cyclones, check out the lists on the World Meteorological Organization's website.
Want to know what the next Atlantic hurricane will be called? Check the National Hurricane Center's website: http://www.nhc.noaa.gov/ .
About Carolina Barnez Gramcianinov:
I am an oceanographer from IO-USP, where I also got my master's degree in Physical Oceanography. I have always been interested in the impact of the oceans on the weather and climate, which motivated me to enter the PhD program in Meteorology at IAG-USP. Since I started as an undergraduate, I fell in love with ocean physics and its impact on other processes. Now in my doctorate, I’ve been charmed by the dynamics and thermodynamics of the atmosphere. I seek to be in between these two environments and I believe that an integrated understanding between these areas is still lacking for a better understanding of the climate system.