The 2017 hurricane season was record-shattering, fueled by abnormally warm ocean water and a particularly conducive weather pattern over the Atlantic. It wasn’t just the most active – it was also the most expensive on record in U.S. history. Although final costs may not be known for years, estimates suggest the tab will run beyond $200 billion.

Four notable storms from the 2017 season had names that will no longer be used for hurricanes, according to the U.N. World Meteorological Organization: Harvey, Irma, Maria and Nate.

Since 1979, the WMO has been using a six-year name rotation. Within a given hurricane season, male and female names alternate; the following year, the gender ordering is staggered (for example, Ana and Bill one year, Alex and Bonnie the next, etc.).

Unless a name is retired, the exact same list of names is used again six years later. However, if a storm gains notoriety because of its strength, number of deaths or damage, the WMO may retire that name from future use. Katrina, Sandy and Isabel have been retired, too.

Harvey, Irma, Maria and Nate will join the list of exceptional hurricane names. They will be replaced by Harold, Idalia, Margot and Nigel.