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Tropical Cyclones: Formation, Structure & Impact on India

Introduction

Tropical Cyclones are intense low-pressure systems associated with strong winds and heavy rain. India, with its 7516 km coastline, is highly vulnerable.

1. Conditions for Formation

• Sea Surface Temperature: Must be above 27°C.
• Coriolis Force: Essential for rotation (hence no cyclones at the Equator).
• Low Wind Shear: Vertical wind speed difference must be low.
• Pre-existing Low Pressure: A seed disturbance.

2. Structure

• Eye: The calm center. No rain, clear sky.
• Eyewall: Surrounds the eye. Strongest winds and heaviest rain occur here.

3. Bay of Bengal vs Arabian Sea

Historically, the ratio was 4:1. Bay of Bengal is shallower and warmer, ideal for cyclones. However, due to Climate Change, the Arabian Sea is heating up, leading to more cyclones like Tauktae and Biparjoy.

Conclusion

Early Warning Systems (IMD) have reduced the death toll (e.g., from 10,000 in 1999 Odisha Super Cyclone to minimal casualties in recent ones).