The fury of nature: A guide to cyclones, hurricanes & tornadoes

Explainer

Ravneet Kaur

TNS

Chandigarh, Updated At : 07:23 PM Jul 04, 2025 IST

Differences between hurricanes, cyclones and tornadoes

Feature	Hurricane / cyclone / typhoon	Tornado
Definition	Large-scale low-pressure systems with organised thunderstorms over warm oceans	Small, intense vortex column formed over land or water
Size	150-1,000 km in diameter	100-500 metres wide (localised)
Duration	Days to over a week	Few minutes to an hour
Wind Speed	120-250 km/h or more	Up to 480 km/h
Formation Area	Over tropical oceans	Mostly over land in mid-latitudes
Other names	Called cyclones (Indian Ocean), Typhoons (NW Pacific), Hurricanes (Atlantic & NE Pacific)	Called tornadoes worldwide
Impact	Widespread: flooding, storm surge, wind	Localised but extremely destructive
Structure	Eye, eye wall, spiral rain bands	Funnel-shaped rotating column

Cyclone naming system

Cyclones are named to improve communication and avoid confusion. Naming is done by regional meteorological organisations such as the IMD (India Meteorological Department) for the North Indian Ocean.

Naming rules

Purpose of naming: To simplify communication, avoid confusion during multiple storms and raise public awareness.
Who names them: Regional Specialised Meteorological Centres (RSMCs) and Tropical Cyclone Warning Centres (TCWCs) under the World Meteorological Organization (WMO).
Naming criteria: Names must be short, easy to pronounce and culturally appropriate.
They should not be offensive, politically sensitive or repeated.
Each region maintains its own pre-approved list of names.
Regional lists: For the North Indian Ocean, the India Meteorological Department (IMD) assigns names from a list contributed by 13 countries, including India, Bangladesh, Oman and others.
In the Atlantic, names rotate every six years unless retired due to severe impact.
Order of use: Names are used sequentially from the list. Once a name is used, it is not reused in that region.
Retirement of names: If a cyclone is particularly deadly or costly, its name is retired and replaced to avoid future distress.

Notable destructive cyclones

Worldwide:

• Typhoon Haiyan (2013) – Philippines; over 6,300 dead.

• Hurricane Katrina (2005) – USA; Rs $125 billion in damages.

• Cyclone Nargis (2008) – Myanmar; Rs 1,40,000 deaths.

• Super Typhoon Tip (1979) – Largest ever recorded.

India:

• 1999 Odisha Cyclone – Over 10,000 deaths.

• Cyclone Amphan (2020) – Rs $13 billion in damages.

• Cyclone Tauktae (2021) – Western coast, major infrastructure loss.

• Cyclone Fani (2019) – Odisha; extensive evacuations minimised casualties.

Cyclone formation & structure

Formation process

Warm ocean water (≥27 degrees C) provides energy.
Air rises due to heating; creates low pressure.
More moist air rushes in, forming a vertical convection system.
Coriolis force (due to Earth’s rotation) causes rotation.
A cyclonic vortex develops; wind spirals inward and upward.

Structure of a tropical cyclone

Key parts

Eye: Calm center (20–50 km); low pressure.
Eyewall: Strongest winds, intense rain.
Spiral Bands: Curved clouds with heavy rain, thunderstorms.

UPSC-style questions

🔹 Short answer questions

What are the different regional names for tropical cyclones?
What is the role of the Coriolis force in cyclone formation?
Mention two destructive cyclones that affected India.

🔹 Long answer questions

Explain the structure and mechanism of formation of a tropical cyclone.
Differentiate between tropical cyclones and tornadoes in terms of origin, structure, and impact.
Discuss the naming system of cyclones in the North Indian Ocean region.

🔹 Analytical/essay type

“Cyclones are natural but their destructiveness is increasingly human-made.” Critically examine with examples.
Discuss how climate change is impacting the frequency and intensity of tropical cyclones in the Indian Ocean region.
What disaster management strategies should be adopted to mitigate cyclone impacts in coastal India?