How Are Cyclones Named in the Indian Ocean? WMO/ESCAP Rules & IMD Facts
The naming of tropical cyclones in the North Indian Ocean basin—encompassing the Bay of Bengal and the Arabian Sea—follows a structured, multilateral meteorological framework designed to eliminate ambiguity during severe weather crises. Historically, tropical storms were designated purely by technical numerical coordinates and geographical latitude-longitude coordinates. However, technical descriptors proved cumbersome for maritime navigators, emergency response personnel, and the general public, frequently causing dangerous confusion when multiple weather systems developed concurrently within the same oceanic basin. To resolve this communication barrier, the World Meteorological Organization (WMO) and the United Nations Economic and Social Commission for Asia and the Pacific (ESCAP) initiated a standardized naming protocol for the region.
The regional naming architecture is managed by the WMO/ESCAP Panel on Tropical Cyclones (PTC), with the India Meteorological Department (IMD) serving as the designated Regional Specialized Meteorological Centre (RSMC) in New Delhi. Established operationally in 2004, the naming mechanism initially comprised eight littoral countries: Bangladesh, India, Maldives, Myanmar, Oman, Pakistan, Sri Lanka, and Thailand. In 2018, the panel was expanded to include five additional nations from the Middle East and Persian Gulf: Iran, Qatar, Saudi Arabia, the United Arab Emirates, and Yemen. In April 2020, the IMD and WMO/ESCAP released an exhaustive list of 169 names, comprising thirteen names submitted by each of the thirteen member states, arranged in a sequential alphabetical grid across thirteen successive columns.
The assignment of a name occurs strictly when a cyclonic disturbance reaches the minimum intensity of a "Cyclonic Storm," characterized by sustained surface wind speeds of at least 34 knots (62 km/h). Naming proceeds sequentially down each column, moving from Bangladesh through India to Yemen, before progressing to the subsequent column. Stringent regulatory criteria govern name selection: proposed names must remain neutral, avoiding political, religious, ethnic, or gender connotations; they must not offend societal sensibilities; and they must not exceed a maximum length of eight letters. In addition, unlike Atlantic hurricanes whose names are recycled on six-year cycles, names assigned in the North Indian Ocean are permanently retired after a single operational deployment. This naming system ensures rapid, clear public hazard communication, facilitating timely community evacuations by disaster management authorities like the National Disaster Management Authority (NDMA).
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Tropical cyclones in the North Indian Ocean (Bay of Bengal and Arabian Sea) are named via a multilateral system organized by WMO and ESCAP.
The WMO/ESCAP Panel on Tropical Cyclones (PTC) was jointly formed in 1972 to coordinate regional meteorological mitigation efforts.
The formal naming of North Indian Ocean tropical cyclones began in September 2004, with the first named cyclone being "Onil" (contributed by Bangladesh).
The India Meteorological Department (IMD) in New Delhi functions as the Regional Specialized Meteorological Centre (RSMC) for tropical cyclone advisories.
The naming panel initially consisted of 8 member countries: Bangladesh, India, Maldives, Myanmar, Oman, Pakistan, Sri Lanka, and Thailand.
In 2018, five new members joined: Iran, Qatar, Saudi Arabia, the United Arab Emirates, and Yemen, expanding the coalition to 13 countries.
In April 2020, IMD and WMO/ESCAP issued an updated list of 169 tropical cyclone names for the North Indian Ocean basin.
Each of the 13 member nations submitted exactly 13 names, arranged in a 13x13 matrix across alphabetical columns.
Names are chosen sequentially down each column from Bangladesh to Yemen before moving to the next column, guaranteeing equitable representation.
A storm receives a name only upon reaching "Cyclonic Storm" strength, with minimum sustained 3-minute surface winds of 34 knots (62 km/h).
Naming rules require proposed names to be neutral and free from political, religious, cultural, or gender bias.
Proposed cyclone names must not cause hurt or distress to any group of people or societal sentiments across member nations.
The maximum allowable length for any proposed tropical cyclone name is strictly capped at eight letters.
Names must be short, phonetically simple, and easy to pronounce clearly across multiple languages during emergency broadcasts.
Unlike Atlantic hurricanes that recycle lists every six years, names used in the North Indian Ocean are never reused; each name is retired permanently.
Cyclone names submitted by India in the 2020 list include Gati, Tej, Murasu, Aag, Vyom, Jhar, Probaho, Neer, Prabhanjan, Ghurni, Ambud, Jaladhi, and Vega.
Historical cyclones named under this system include Cyclone Phailin (2013, Thailand), Cyclone Hudhud (2014, Oman), and Cyclone Fani (2019, Bangladesh).
Cyclone Biparjoy (2023, meaning "disaster" in Bengali) was named by Bangladesh and became the longest-lived cyclonic storm in the Arabian Sea since 1977.
Cyclone Michaung (December 2023), which made landfall in Andhra Pradesh, was named by Myanmar to signify resilience and strength.
The primary objective of assigning names instead of geographic coordinates is to eliminate public confusion and streamline early warning advisories.
Naming enhances mass media communication, supporting prompt community evacuations by authorities such as the NDMA and SDRF.
In the Southern Indian Ocean (south of the Equator), tropical cyclones are named independently by meteorological centers in Mauritius, Madagascar, and Australia.