The super-active 2005 and 2020 hurricane seasons were both so busy that some storms were named using the Greek alphabet. But problems arose in 2020, leading to a new list of names to roll into.

Each hurricane season has a list of 21 names for tropical storms. The 2005 and 2020 seasons were so active that we ran through all 21 names. In both years, the additional storms used the Greek alphabet for their names, starting with Alpha.

A World Meteorological Organization (WMO) committee, which develops the lists of names, originally decided that Greek names would be reused whenever the situation arose and wouldn’t be retired. However, the name and year–such as Eta (2020)–could be retired.

In 2005, six storms used the supplemental names list, but none were destructive enough to retire. In 2020, 10 storms used the supplemental list. Two of them, Eta and Iota, were retired.

The WMO determined that the record-breaking 2020 season made clear some issues with using Greek names. Translation into other languages, as well as similar pronunciations of different Greek letters, proved challenging. They also noted too much focus on the names themselves, rather than the impacts and related safety information.

Because of the problems with using the Greek alphabet, the WMO developed a new supplemental list of names.

It is similar to the usual rotating list: 21 names, alternating between what are typically female and male names, running from A to W. Any storm that rises to the level of being retired will simply have a new name take its place on the list.