However, a few letters are missing. Neither Q, U, X, Y, or Z will get the chance at being the lead letter of an Atlantic storm’s name. That’s for one simple reason: retirement. There simply aren’t enough names beginning with those five letters to provide a reasonable series of backups in the event of a hyperactive hurricane season, such as in 2005. That year, meteorologists exhausted all 21 names, forcing the six storms that followed to receive Greek letters (the standard protocol).