Weather, April 2021
Keeping Score on Hurricane Names
In the last newsletter I speculated on the possible retirement of hurricane names over the past two Atlantic hurricane seasons. Recall that it is the World Meteorological Organization (WMO) that generates the lists of names that are used for tropical cyclones around the world, and because of the Covid-19 pandemic, they had been unable to meet after the 2019 hurricane season to decide which names should be retired from the list because the storms were particularly impactful in terms of property damage and/or loss of life. The WMO committee in charge of this task finally met (virtually) in March of 2021 and made their decisions.
For the 2019 season, I had suggested that Dorian, which produced catastrophic damage in the northwestern Bahamas as a slow-moving category 5 hurricane, and perhaps Humberto, which impacted Bermuda with hurricane conditions, could be retired. The committee did decide to retire Dorian, but Humberto was not removed from the list. Dorian was kind of a slam-dunk, but I’m not surprised that Humberto wasn’t retired. So I give myself a reasonable grade on that season.
For the 2020 season, I had suggested that several systems had the potential to be retired. The committee decided to retire three names from this season: Laura, which struck southwestern Louisiana and southeastern Texas as a major hurricane; Eta, which made landfall in Nicaragua just short of category 5 status; and Iota, which struck Nicaragua in almost the same spot as Eta as a devastating category 5 hurricane. Of the other suggestions I made: Isaias, which impacted a large portion of the Bahamas and the eastern U.S.; Paulette, which made a direct hit on Bermuda; Sally, which impacted southwestern Alabama and the western Florida panhandle as a category 2 hurricane; Delta, which crossed the northeastern Yucatan peninsula as a major hurricane then went on to make landfall in southwestern Louisiana; and Zeta, which also crossed the northeastern Yucatan peninsula then made landfall in southeastern Louisiana just below category 3 status; none were deemed impactful enough to be retired. So my score for the 2020 season was not so good.
In addition, I had opined that there was a reasonable chance that the record of five names retired in one season could be at least equaled, but this did not occur.
It is interesting to look back at previous names that have been retired and compare them with some of the systems that did not “make the grade” for the 2020 season. For example, hurricane Bob in 1991 tracked north-northeast off the east coast of the U.S., reaching its peak strength east of Cape Hatteras with top sustained winds of 100 knots (category 3) then weakened to a category 2 hurricane when it made landfall near Newport, R.I., and was a tropical storm when it crossed the Maine coast near Penobscot Bay. This storm produced a good deal of damage in the eastern U.S., particularly in New England, but also including North Carolina, and there were 17 fatalities associated with Bob. In the storm summary generated in the aftermath of the storm, it was estimated that the property damage ($1.5 billion estimate at that time) would rank as 13th or 14th on the all-time list, adjusted for inflation.
In 1985, hurricane Gloria tracked from the Cabo Verde Islands in the tropical eastern Atlantic westward, then turned northwest and passed well north of the Leeward Islands and Puerto Rico, and east of the Bahamas. It turned north to the east of the southeastern U.S. and made a brief landfall at Cape Hatteras, then headed north and crossed western Long Island before tracking through interior New England. Its peak intensity occurred when it was located well to the east of the Bahamas with top sustained winds of 125 knots (category 4), but it then weakened and by the time it made landfall at Cape Hatteras it was a category 2 system, and it transitioned to an extra-tropical system once inland over New England. A preliminary property damage estimate of about $1 billion (not adjusted for inflation) was included in the official storm summary produced in late 1985.
I note these two storms because their paths along and near the east coast of the U.S. were somewhat similar to that of Isaias in 2020. But Isaias was not retired. I believe this has a great deal to do with the increase in hurricane impacts over the past couple of decades. Gloria and Bob both occurred during a time when hurricane frequency was considerably lower compared with the past 20 years. As a result, their impact stood out as quite consequential during the time period when they occurred. As noted above, the property damage produced by Bob was estimated to be high enough to rank 13th or 14th on the all-time list. Examining the most recent ranking of U.S. property damage caused by hurricanes which includes the 2020 season (available at this link: www.ncdc.noaa.gov/billions/dcmi.pdf) reveals that, adjusted for inflation, the list of the top 48 storms now does not include Bob or Gloria. However, it does include Isaias, as well as three other storms from the 2020 season: Laura, Sally, and Zeta. It is not unreasonable to assume that all of these names may very well have been retired had the storms occurred during a less active hurricane period. Note that Eta and Iota are not on the list due to the fact that they did not cause any damage in the U.S.; their impact was confined to Central America.
Another issue I raised in my previous newsletter had to do with the use of the Greek alphabet when the seasonal list of names was exhausted. I noted that retiring a storm name from the Greek alphabet would be difficult since there was no way to replace the name with a different Greek letter. The WMO recognized this issue and raised other issues with the use of the Greek alphabet for naming storms. In particular, during the 2020 season there were storms with very similar sounding names (Zeta, Eta, Theta) which occurred in the same general time period, with Eta and Theta existing simultaneously for a few days, and this had the potential to confuse the public, which is antithetical to the rationale for using storm names in the first place. Therefore, the WMO has decided to discontinue the use of the Greek alphabet for future seasons and will instead draw from a supplemental list of names whenever the primary list for a given season is exhausted. Here is a link to the new supplemental lists for the Atlantic and the eastern Pacific: public.wmo.int/en/media/news/supplemental-list-of-tropical-cyclone-names-raiv
As noted in the previous newsletter, if you keep a boat in the water, or own property along or near the coast, having advance plans and arrangements in place for tropical cyclones will put you in a better position to act decisively should one of these systems pose a threat. There is still some time to formulate a plan before the onset of the 2021 hurricane season, and as recent seasons have shown, it will be best to be ready.
Contributing editor Ken McKinley is a weather router and owns Locus Weather in Camden, Maine.