What is a cyclone, hurricane and a typhoon?
The short answer is that they are all the names for the same storm system. A tropical cyclone is a rotating storm system that has a low-pressure centre. It is characterized by strong winds, spiral arrangements of the thunderstorm, and heavy rainfall.
When this storm develops in the Atlantic Ocean and northeastern Pacific Ocean it is called a hurricane, in the north-western Pacific Ocean is called a typhoon and in the south Pacific or the Indian Ocean is referred to as "tropical cyclones" or "severe cyclonic storms.
How are they named?
For most of the time in history, storms were unnamed and referred to arbitrarily, but it was later found that naming storms helped in making warning systems efficient as the storms could easily be identified and that short and distinctive names had a better recall.
In modern times, there is a proper procedure and authoritative bodies that determine the names of tropical cyclones and hurricanes. For tropical cyclones such as the present one, the Tropical Cyclone Regional Body responsible for that basin will finalise the names in its annual or biennial meeting. There are 5 tropical cyclone regional bodies- ESCAP/WMO Typhoon Committee, WMO/ESCAP Panel on Tropical Cyclones, RA I Tropical Cyclone Committee, RA IV Hurricane Committee, and RA V Tropical Cyclone Committee.
Similarly, there is a Hurricane Committee to determine names of hurricanes. The names that are selected does not represent any person and it is ensured that it is familiar to the people in the region. After criticism about using only female names for naming storms male names were also included in the list.
So why was the name Amphan chosen?
According to information from WMO, in 2000, WMO/ESCAP Panel on Tropical Cyclones at its twenty-seventh Session held in 2000 in Muscat, Sultanate of Oman agreed to assign names to the tropical cyclones in the Bay of Bengal and Arabian Sea. And the naming began from 2004 with inputs from eight members. Since that time five more countries have joined the panel, making it a total of 1 country.
Amphan happens to be the last name on that pre-determined list and the first one to be used in the year 2020. You may also remember others such as Fani and Maha which were also from the list.
In the future the tropical cyclones will named from a new list of 169 names which starts with the name Nisarga, then Gati followed by Nivar. There is also Shaheen, Gulab, Tej, and Aag in the list. The entire lists for cyclone names are given on the WMO website.
The RSMC New Delhi Tropical Cyclone Center is responsible to name the tropical cyclones that have formed over the Bay of Bengal and the Arabian Sea when they have reached the relevant intensity.