Consequences of Tropical Cyclones

The energy that drives a tropical cyclone comes from the latent heat released by warm, moist air. This single fact explains why the cyclone's power fades as it moves inland. The farther a cyclone travels from the sea, the weaker it becomes, because its fuel supply — the warm, moisture-laden air over the ocean — is cut off.

In India, this means the force of a cyclone decreases with increasing distance from the Bay of Bengal and the Arabian Sea. It is the coastal areas that bear the brunt of these storms. These regions are often struck by severe cyclonic storms with an average velocity of 180 km/h. Such intense winds, combined with the low pressure at the storm's centre, can push ocean water abnormally high along the coast. This sudden, abnormal rise in sea level is known as a storm surge, and it is often the most destructive part of a cyclone, flooding low-lying coastal land with seawater.

Beyond the immediate destruction, cyclones also play a role in worsening floods. The heavy rainfall they bring, along with the storm surge, adds to the intensity, magnitude, and gravity of flood events in the affected regions. Many states in India face heavy loss of lives and property due to these recurrent floods.

The scale of the problem was formally recognised when the Rashtriya Barh Ayog (National Flood Commission) identified 40 million hectares of land in India as flood-prone. Some states are particularly vulnerable. Assam, West Bengal, and Bihar are among the high flood-prone states of India. In addition, most of the rivers in the northern states, such as Punjab and Uttar Pradesh, are also vulnerable to occasional floods. …