August 23, 2005 near the coast of the Bahamas formed a tropical depression. Six days later, after landing on land in southern Florida as a third category hurricane, Katrina struck Louisiana by winds at speeds of up to 225 km / h. The hurricane left behind a huge trail of destruction and sacrifice and deprived almost half a million people of roofs over their heads.
According to the National Hurricane Center of the United States, Katrina cost the country more than any tropical cyclone that the US has ever attacked, and has become the third weather system by the number of victims. The World Meteorological Organization decided to remove the name of the deadly hurricane from the list of hurricane names forever.
In what case are the names of hurricanes removed from the lists? And how do hurricanes get their names at all?
Meteorologist Dan Kottlovski explains how the system of name of hurricanes works and where this tradition came from. “During the Second World War, the US lost ships in the west of the Pacific because of hurricanes,” Kottlovski said. – A lot of research has been done to understand these storms, and to make people aware of them. During the project, the military began to give them names. ” Kottlovski explains that initially these names were based on the phonetic alphabet of the military. However, since 1979, the World Meteorological Organization has begun to use a repetitive system of human names to standardize the process.
The system works differently depending on where the storm is formed.
Hurricanes in the Atlantic basin receive names based on six lists of 21 names in alphabetical order (the letters Q, U, X, Y and Z are skipped). These lists have a six-year rotation, so every seventh year, meteorologists return to the first list. If during a single hurricane season more than 21 hurricanes are formed (the last time it was in 2005), the Greek alphabet is used to name the remaining storms.
In the eastern part of the Pacific Ocean, the same cyclic system of lists is used; However, the lists consist of 24 names (only Q and U are omitted). For each letter, different names from the Atlantic are used to better represent the traditions of this region.
The exception is the central-eastern part of the Pacific Ocean. Hurricanes in this region are named on the basis of four 12-name lists, and they get names one by one, starting a new list only when the previous one comes to an end.
To get the name, the system should have stable winds at a speed of 63 km / h. When the wind speed exceeds 117 km / h, the storm is officially called a hurricane.
Storms with speeds below 62 km / h are called tropical depressions, which are not given names.
As for the names of hurricanes removed from the lists, Kottlovski explains that the process, although subjective, is ongoing. “Almost every strong, devastating hurricane that the US has ever attacked has been removed from the list,” he says. “These names are replaced by others.”
The decision to remove the name from the hurricane list is taken at the annual conference of the World Meteorological Organization. A complete list of hurricane names with a breakdown by basins can be found here.