The 2020 Atlantic Hurricane Season

The 2020 Atlantic Hurricane Season has ended, and there have been much written about the record setting number of named storms. There are several issues with the numbers based on named hurricanes. The problem is that these are based on shifting criteria (naming) and technology (wind speed measurements) that tend, in my opinion, to make recent seasons (especially since 2000) look worse than they really are in context. While it was a very active season with significant damage and impact, the total number of storms is a bit exaggerated – several storms would probably not have been named using the criteria prior to the mid 2000’s. Here are a couple of other ways of looking at things to put the season in perspective.

One measure of the intensity of a season is the Accumulated Cyclone Energy (ACE) index. It is summing the square of the wind speed for each storm at six hour intervals (recalling that the kinetic energy is related to the square of the wind speed). By that measure the 2020 season is the 13th most active since the mid 1800’s – with the caveat we know there is an undercount of storms, and likely an underestimation of intensity (by modern standards) as well, especially for storms that did not make landfall. So more than likely 2020 was still in the top 20, but probably not above 15th.

What about damage? By that measure, if we use the existing distribution of population and infrastructure for past storms, again we have a bad season (especially for the Gulf Coast and Central America), but depending on how you crunch the numbers far from record setting. 2020 just breaks the top 10 in total damage.

Estimated Economic Impact of Tropical Cyclones in the Atlantic

It does better if you use the criteria of the number of people who experienced tropical storm force winds, coming in at number two, but that is a bit misleading because many people are counted twice (or even three times) since Central America and Louisiana were hit by more than one intense storm. Taking the double counts out it drops to eighth (2012 is by far number one due to the broad Sandy wind field sweeping through the densely populated northeast).

Estimated population experiencing tropical storm winds or greater

So the official Atlantic season ended on November 30th. There is still an invest area in the far eastern Atlantic that has winds well above tropical storm strength, but it does not really have tropical characteristics so has not been named. There is a cyclone at tropical storm strength about to make landfall on Ceylon today, followed by southern India. And the southern hemisphere season is kicking off … the world keeps turning and the seasons change, but there are always weather disasters going on somewhere. For the Blog, will continue to report on cyclones and earthquakes of course, but will be posting more on winter storms in the coming weeks. Interestingly, for many years the biggest property insurance loss numbers come from broken pipes … and you haven’t really experienced terror until you’ve driven the perimeter in Atlanta (much less navigated Spaghetti Junction) with so much as a single ice crystal sighted in Marietta 😛

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