The names of hurricanes are re-used every 6 years unless they are retired.
Names of particularly severe and/or damaging hurricanes are not re-used. The decision whether to remove a name is made yearly at an annual session of the Hurricane Committee.
When a name is retired/removed from the list, a new name starting with the same letter is chosen to add to the list in its place.
They simply start with 'A' again - using a different name from the previous choice.
Until the hurricane dies away
Yes. The name Katia was used for hurricanes in 2011 and 2017.
Currently hurricanes are named by the World Meteorological Organization in Geneva. They have 6 lists kept in rotation that are used to name any hurricanes that happen during the year.
Yes. Particularly destructive or memorable storms have their names "retired" ... there probably won't be another Andrew, or Katrina, or Sandy. But storms that dissipate at sea may have their names used again.
Yes, if a storm doesn't cause much damage, its name may be used again and returned to the annual rotation. Names become available for reuse once every six years. Hurricanes that cause serious damage or loss of life will have their names "retired" upon review of the hurricane season and will never be used again.
The letters Q, U, X, Y, and Z
We usually name hurricanes, so that if there are multiple hurricanes occurring simultaneously, it won't be confusing and it might protect people.
No, All hurricanes have different names and do not repeat the same name.
There were four hurricanes named Lili, in 1984, 1990, 1996, and 2002. There were three hurricanes named Lily in 1967, 1971, and 1975. Lili was used for storms in the Atlantic Ocean; Lily was used for hurricanes in the eastern Pacific Ocean. No hurricanes have been named Lilly by that spelling.
Cause they do.
These instruments are called dropsondes.