What is the Fujiwhara effect? Explain its impact on the movement and intensity of tropical cyclones

Theme

T31 Tropical cyclones, twisters & cyclone warnings

What UPSC asks in this theme

Questions repeat on cyclone formation and location (SST rise, Fujiwhara effect, Bay of Bengal vs Arabian Sea), twisters in the Gulf of Mexico, and IMD colour-coded warnings.

What to cover

• Conditions for tropical cyclones: SST above 26–27°C, Coriolis, low wind shear
• Why Bay of Bengal, South China Sea, Gulf of Mexico
• Fujiwhara effect
• Tornadoes vs cyclones
• IMD warnings and cyclone naming
• Odisha's cyclone management success

Writing the answer

• Use a diagram of a cyclone's structure; end with preparedness

These notes are for the whole theme, built from all 5 of its PYQs. UPSC does not publish model answers.