A Wisconsin Expat's Perspective on Atlantic Basin Hurricane Trends

Devrah Arndt, PhD

Figure 1: Hurricane Matthew.

​I have only lived in Florida for three years, but I have had the privilege of witnessing the landfall of four major hurricanes since living here. Hurricane Matthew formed on October 1st, 2016 and skirted the entire east coast of Florida (Fig. 1). Hurricane Irma formed September 5th, 2017 and sent the entire state of Florida into a panic. Irma was HUGE and it wasn’t clear which coastline would be impacted, resulting in the evacuation of more than a third of the state’s population with just two days before landfall. Hurricane Maria formed just weeks later on September 18th, 2017 and tore through regions that were already battered from Hurricane Irma (most notably Puerto Rico). Hurricane Michael formed October 7th, 2018 and made making Category 5 status (157 mph+). Three of these four hurricanes had their names retired by the World Meteorological Organization (Matthew, Irma, and Maria), and Hurricane Michael is also currently being considered for retirement at the time of this writing.
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​I reside in Gainesville, FL – a city that is a two hour drive from the Atlantic coast and from the Gulf coast. My central location in Florida has buffered me from direct exposure to category 4 and 5 force hurricane winds, but I have experienced the hysteria that goes along with these devastating natural disasters. I have seen grocery stores run out of water and produce. I have sat in line at a gas station to get gas, and I have seen gas stations run out of gas completely (Fig. 2). I have lost power for over 24 hours when it was 100 °F outside. I remember listening to the radio shortly before Irma made landfall and hearing an older woman beg a radio host for help after she was abandoned in an evacuated county. Shortly after Hurricane Michael hit, I drove through the Florida panhandle to get to a volleyball tournament in Destin – the 25 miles where Michael’s eye made landfall looked like a tree lawnmower had come through and leveled all the trees (Fig. 3). After thinking I’d driven through the worst of it, I stopped in Marianna to get McDonalds; however, the restaurant was damaged and the whole city was under a 6 pm curfew. Everyone in the town looked like a zombie…and not superficially, but like real zombies. I didn’t belong there, I was too clean and well-rested. The atmosphere was somber, the sounds and colors were muted – I was a natural disaster tourist and I couldn’t wait to get out of there. 

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Figure 2: Photos taken from areas in Florida impacted by Hurricane Irma.

Figure 3: Photos taken from areas in Florida impacted by Hurricane Michael.

I’m huge fan of Stephen King, and I couldn’t help but feel like I was living in one of his apocalyptic novels when these major hurricanes hit. I am originally from the Midwest – specifically Wisconsin – and I had never experienced anything like this before, let alone multiple times. I have to ask the question if this is normal? ​

​Public documents on Atlantic hurricane history are available from the National Hurricane Center (NHC), the National Weather Service (NWS), and the American Meteorological Society. For the purposes of this blog post, I pulled summarized data from tables in Wikipedia on hurricanes in the Atlantic Basin, but if I was going to publish this data in a peer reviewed journal I would be using the data from official sources. ​

Figure 4: Hurricanes trends over time.

Reliable tropical cyclone record keeping started in 1851, satellite tracking started in 1962, hurricanes were given names in 1953, and the Saffir-Simpson scale was developed in 1971. A total of 925 hurricanes developed in the Atlantic basin since record keeping began in 1851. When these hurricanes are graphed by decade (Fig. 4a), there are no clear changes in the number of hurricane occurrences over time. Peak decades for the development of hurricanes appear at 50-70 year intervals and include 1880-1889, 1950-1959, and 2000-2009.
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Of the 925 hurricanes that have occurred since 1851, 153 of them had wind speeds greater than 130 mph (category 4 and 5 on the Saffir-Simpson scale). When these 153 storms are graphed by decade, there is a clear trend for more strong storms to occur in more recent decades (Fig. 4b), and the first category 5 hurricane (sustained winds of 157+ mph) wasn’t recorded until the 1920’s (Fig. 4c). 

The 2019 hurricane season hasn’t happened yet, but if you graph the nine years that have been recorded so far in this decade (Figure 5, uncolored bars), this past decade is going to match or exceed previous decades in the number of hurricane occurrences and the number of strong hurricane occurrences. So to answer my question… Is this normal? If I only consider the last 20 years, then yes I would say that my exposure to strong hurricanes over the last three years in Florida is normal. However, if I compared my hurricane exposure to anyone who lived in the Atlantic basin before 1930, I would say that my exposure to strong hurricanes is abnormal.

I feel lucky that I live in an era with the infrastructure (building codes) and technology (warning systems) that can significantly improve my chances of survival in one of these storms. However, I can also see the irony in the relationship between today’s improved infrastructure and technology with the Industrial Revolution of the 1800’s, and the absence of pre-industrial era strong Atlantic hurricanes coupled with the presence post-industrial era strong Atlantic hurricanes. Between 1800 and 2019 the world’s population grew from 1 billion to 7.7 billion. Industrialization and urbanization in the late 1800’s expanded agricultural markets, and the number of farms in the U. S. quadrupled from 1.4 million in 1850 to 6.4 million in 1910. The world also witnessed the advent of the automotive industry in the 1890’s. It would be irresponsible to not at least mention the correlation (and likely causation) between the events of the industrial revolution (1760-1900) and the onset of strong hurricanes in the Atlantic basin. Though it is outside the scope of this blog post, there is a wealth of data and evidence linking climate change to the onset of stronger and more destructive hurricanes [1-7]. 

Cited References
1. Bender, M.A., et al., Modeled impact of anthropogenic warming on the frequency of intense Atlantic hurricanes. Science, 2010. 327: p. 454-458.
2. Elsner, J.B., Evidence in support of the climate change–Atlantic hurricane hypothesis. Geophysical Research Letters, 2006. 33(16).
3. Holland, G. and C.L. Bruyère, Recent intense hurricane response to global climate change. Climate Dynamics, 2013. 42(3-4): p. 617-627.
4. Mousavi, M.E., et al., Global warming and hurricanes: the potential impact of hurricane intensification and sea level rise on coastal flooding. Climatic Change, 2010. 104(3-4): p. 575-597.
5. Murakami, H., et al., Simulation and Prediction of Category 4 and 5 Hurricanes in the High-Resolution GFDL HiFLOR Coupled Climate Model*. Journal of Climate, 2015. 28(23): p. 9058-9079.
6. Trenberth, K.E., et al., Hurricane Harvey Links to Ocean Heat Content and Climate Change Adaptation. Earth's Future, 2018. 6(5): p. 730-744.
7. Wuebbles, D.J., et al., Severe weather in the United States under a changing climate. EOS, 2014. 95(18): p. 149-150.

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