The World Meteorological Organization recently announced that the names of tropical storms are now being pulled from the Greek alphabet due to officially reaching the end of the alphabetical list of 21 Atlantic tropical storm names for 2020 (the last tropical storm name on the list was Wilfred). This is only the second time the Greek alphabet has been used to name storms – the first time was during the 2005 hurricane season, where the last named storm was Zeta, according to the National Oceanic and Atmospheric Administration.

Of course, there’s science as to how a tropical storm forms into a hurricane. There are four stages to a hurricane: a tropical disturbance, a tropical depression, a tropical storm, and the hurricane. You can learn more about tropical definitions here.

What’s the history behind naming storms? There’s a list of names for Atlantic hurricanes for every six years, meaning one list is repeated every seventh year. It is important to note that if a storm is deadly or costly, that particular name is retired. Atlantic tropical storms are maintained and updated through the international committee of the World Meteorological Organization. Read more about the history of hurricane names + retired hurricane names here.

It’s still hurricane season (until November 30), so make sure to take a look at this list to be prepared.