Geography & BiodiversityImportant2025-11-26

Formation of Cyclonic Storm Ditwah in Bay of Bengal

In News

What Happened

On November 26, 2025, Cyclonic Storm Ditwah formed over the Southwest Bay of Bengal, fueled by unusually warm sea surface temperatures. Moving atypically, it caused catastrophic flooding in Sri Lanka before tracking parallel to the Tamil Nadu and Andhra Pradesh coasts. The storm was named 'Ditwah' by Yemen, honoring the Ramsar-protected Detwah Lagoon in the Socotra Archipelago.

Why It Matters

The storm's atypical track and intense precipitation highlight the growing unpredictability of regional weather events due to changing oceanic conditions. The widespread IMD red alerts emphasize the persistent vulnerability of India's eastern and southern coastlines to extreme cyclonic disruptions, requiring constant vigilance and robust disaster preparedness.

Background

History & Context

The naming of cyclones in the North Indian Ocean is managed by the WMO/ESCAP Panel on Tropical Cyclones. The naming system began in 2004 with eight member nations. In 2018, the panel was expanded to include five more countries, including Yemen. In April 2020, a new list of 169 names was adopted, featuring 13 suggestions from each of the 13 member nations, ensuring names are culturally relevant but politically and religiously neutral.

What Changed

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BEFORE: Prior to 2018, only eight nations (including India, Bangladesh, and Oman) contributed names for North Indian Ocean cyclones. NOW: The WMO/ESCAP panel includes 13 countries, with Yemen, Iran, Qatar, Saudi Arabia, and the UAE actively contributing to the naming roster (such as 'Ditwah').
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BEFORE: Tropical cyclones often followed predictable, historical trajectories toward specific coastal landing zones. NOW: Altered climatic variables, like unusually high sea surface temperatures and low vertical wind shear, are increasingly facilitating atypical tracks that parallel coastlines and prolong inland impacts.
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BEFORE: Cyclones were historically identified using technical coordinates or numbers, which hampered rapid public communication. NOW: Cyclones receive concise, geographically or culturally significant names to rapidly raise public awareness and streamline emergency responses.

Prelims Angle

NCERT Connection

This event directly connects to NCERT Class 11 Physical Geography, Chapter 10 (Atmospheric Circulation and Weather Systems). Cyclonic Storm Ditwah serves as a practical example of the conditions requisite for tropical cyclone genesis—specifically, the necessity of warm sea surface temperatures, low vertical wind shear, and the Coriolis force to maintain the low-pressure system.

Practice Questions

Q1

Correct Statement(s)

With reference to the formation of Tropical Cyclones and the WMO/ESCAP naming convention, consider the following statements: 1. Tropical cyclones require high vertical wind shear to develop and intensify over the ocean. 2. The WMO/ESCAP Panel on Tropical Cyclones for the North Indian Ocean includes Yemen, which contributed the name 'Ditwah'. Which of the statements given above is/are correct?

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