A tropical cyclone is a rapid rotating storm originating over tropical oceans from where it draws the energy to develop. It has a low pressure centre and clouds spiraling towards the eyewall surrounding the “eye”, the central part of the system where the weather is normally calm and free of clouds. Its diameter is typically around 200 to 500 km, but can reach 1000 km. A tropical cyclone brings very violent winds, torrential rain, high waves and, in some cases, very destructive storm surges and coastal flooding. The winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere
How are they formed
- Tropical cyclones are formed only over warm ocean waters near the equator. When warm, moist air over the ocean rises upward from near the surface, a cyclone is formed.
- When the air rises up and away from the ocean surface, it creates an area of lower air pressure below. It causes the air from surrounding areas with higher pressure to move towards the low-pressure area which further leads to warming up of the air and causes it to rise above.
- As the warm, moist air rises and cools the water in the air forms clouds. The complete system of clouds and wind spins and grows, along with the ocean’s heat and water evaporating from the ocean surface.
- As the wind system rotates with increasing speed, an eye gets formed in the middle. The centre of a cyclone is very calm and clear with very low air pressure. The difference of temperature between the warm, rising and the cooler environment causes the air to rise and become buoyant.
Impact on India
- In coastal areas, the cyclone kills many people and destroys property.
Economic losses include a loss of livelihood for fishermen as well as a negative impact on the tourism industry.
- Affects the entire social well-being of people living along the coast. Schools and hospitals remain closed, and damage to coconut plantations that takes years to recover throws farmers’ lives into disarray every time a cyclone strikes.
- Animals and birds in the sea are being harmed. Chilika Lake, India’s largest coastal lagoon and a haven for migratory birds, is also in the high risk zone.
- In 2005, the country passed new legislation to establish the National Disaster Management Authority, a centralised agency tasked with responding to and mitigating the effects of disasters.
- In 2006, India established the National Disaster Response Force (NDRF), a specialised corps of highly trained men and women dedicated to disasters such as cyclones and earthquakes.
- Creating an Early Warning Dissemination System (EWDS) and increasing coastal community capacity.
- Infrastructure in cyclone-prone areas must be built/designed in such a way that evacuation is simplified and damage is minimised.
- Forecasting techniques must be improved in order to allow for more time to prepare before a cyclonic storm.
- Individual preparedness can be improved by organising school and social awareness campaigns in vulnerable areas.
- To play a better role in keeping themselves and others safe, the NDRF and other emergency forces must be better equipped with emergency kits and modern machinery.
- The imperative for India now is not only to have resilient, functional infrastructure that can recover after a disaster, but also to have infrastructure that can withstand and operate during a crisis.
How to structure:
- 1) Give the definition of tropical cyclones
2) Give the reasons for its formation- use diagrams
3) Explain how it affects India
4) Mention relevant government organizations
5) Suggest way forward and conclude