As of October 2024, Cyclone Dana is poised to make landfall along the Odisha coast, particularly near Bhitarkanika National Park. The India Meteorological Department (IMD) has classified it as a severe cyclonic storm, with wind speeds reaching up to 110 km/h and potential storm surges of 2 metres. This cyclone marks the third formation in the North Indian Ocean for the year and is notably the first in the post-monsoon season, raising concerns over its impact on the coastal communities of Odisha and West Bengal.
About Cyclones
A cyclone is a large-scale air system characterised by a low-pressure centre and spiralling winds. In the Northern Hemisphere, these winds rotate anticlockwise, while in the Southern Hemisphere, they rotate clockwise. Cyclones can be broadly categorised into two types: extratropical and tropical.
Extratropical Cyclones
Extratropical cyclones, also known as mid-latitude cyclones, typically form outside the tropics and are associated with cold air at their core. These cyclones derive energy from the interaction of warm and cold air masses, often resulting in fronts that can lead to varied weather conditions, including severe storms. They can occur over both land and ocean, impacting weather patterns.
Tropical Cyclones
Tropical cyclones develop in regions between the Tropics of Cancer and Capricorn. They are the most destructive storms, gaining strength from warm ocean waters. The energy derived from the condensation of water vapour fuels these storms. Unlike extratropical cyclones, tropical cyclones do not have associated fronts and are classified by their intensity, with names varying by region—hurricanes in the Atlantic and typhoons in the Pacific.
Cyclone Dana’s Characteristics
Cyclone Dana exhibits several meteorological features indicative of intense rainfall and strong winds. The IMD has noted convection in the cyclone’s western sector, which may lead to exceptionally heavy rainfall, particularly in Odisha and West Bengal. The Madden-Julian Oscillation (MJO), an important atmospheric phenomenon, is currently in a phase conducive to increased rainfall, further complicating the potential impact of Dana.
Historical Context and Community Preparedness
The impending arrival of Cyclone Dana coincides with the 25th anniversary of the catastrophic 1999 super cyclone that devastated Odisha, claiming thousands of lives. This historical context has heightened awareness and preparedness among coastal communities. Many residents are now more informed about cyclone warnings and have access to improved infrastructure, including cyclone shelters built post-1999. Lessons learned from past disasters have encourageed a culture of resilience, with communities actively engaging in evacuation and safety measures.
Impact on Agriculture and Freshwater Sources
The storm surge accompanying Cyclone Dana poses an important risk to low-lying coastal areas, potentially leading to the inundation of agricultural lands and the salinisation of freshwater sources. This can have long-term impacts on local agriculture, which is vital for the economy and sustenance of these communities. The interplay of storm surges and intense rainfall can lead to flash flooding, further exacerbating the situation.
Questions for UPSC:
- Discuss the classification of cyclones and their impact on coastal communities in India.
- Analyse the role of the Madden-Julian Oscillation in influencing rainfall patterns during cyclonic events.
- Evaluate the preparedness measures taken by coastal Odisha communities in response to historical cyclones.
- Examine the ecological consequences of storm surges on agriculture and freshwater resources.
- What are the differences between extratropical and tropical cyclones in terms of formation and impact?
