Indian cyclones: case studies

Detail

Key terms used in this section

• Tropical cyclone: a very large low-pressure storm that forms over warm tropical seas. Winds spiral inwards around a calm centre (the eye). They turn anticlockwise in the northern hemisphere.
• Landfall: the moment the centre (eye) of a cyclone crosses the coastline from sea to land.
• Storm surge: a sudden rise of sea water that cyclone winds push onto the coast. It floods low-lying land and is the biggest killer in most cyclones.
• IMD intensity ladder (weakest to strongest): Depression → Deep Depression → Cyclonic Storm → Severe Cyclonic Storm → Very Severe Cyclonic Storm (VSCS) → Extremely Severe Cyclonic Storm (ESCS) → Super Cyclonic Storm (SuCS).
• Rapid intensification: a cyclone gaining strength very fast. IMD's working measure is a rise in wind speed of about 30 knots (55 km/h) in 24 hours [2].
• Bay of Bengal (BoB) vs Arabian Sea: more cyclones form in the BoB, and they are usually stronger. The Arabian Sea gets fewer, but they are now becoming more frequent and lasting longer.

Comparison table

Cyclone	Sea, date	Landfall	Peak	Key lesson
Odisha super cyclone (1999)	Bay of Bengal, 29 Oct 1999	Near Paradip, Odisha	Super cyclonic storm, winds over 250 km/h	About 10,000 deaths. Led to OSDMA, cyclone shelters and community volunteers
Ockhi (2017)	Formed near Sri Lanka, late Nov 2017	Did not cross the mainland; passed through the Lakshadweep Sea	Rapid intensification	Came with little warning; many Kerala and Tamil Nadu fishermen killed or missing at sea
Fani (2019)	Bay of Bengal, May 2019 (pre-monsoon)	Near Puri, Odisha, 3 May 2019	Extremely severe	IMD forecasts and evacuation of over a million people kept deaths low. Praised by the UN
Amphan (2020)	Bay of Bengal, May 2020	West Bengal–Bangladesh coast across the Sundarbans, 20 May 2020	Super cyclonic storm	First SuCS in the Bay since 1999. Hit during the COVID-19 lockdown. Mangroves softened the surge
Biparjoy (2023)	Arabian Sea, June 2023 (about 13 days long)	Near Jakhau port, Kachchh, Gujarat, 15 June 2023	Extremely severe	"Zero casualty" approach with mass evacuation

1. Odisha super cyclone (1999): the turning point

• What happened
• It struck near Paradip (Jagatsinghpur district, Odisha) on 29 October 1999.
• It was a super cyclonic storm, with winds over 250 km/h and a storm surge several metres high.

• About 10,000 people died. Most drowned in the surge on the flat, low Mahanadi delta coast.

• Why the death toll was so high: warnings did not reach every village → there were few strong buildings to shelter in → people stayed in mud houses on low ground → the surge swept far inland.

• What Odisha changed afterwards
• It set up OSDMA (Odisha State Disaster Management Authority, 1999). This was India's first state disaster management authority, created six years before the national Disaster Management Act, 2005.
• It built a network of multipurpose cyclone shelters. These are raised concrete buildings that serve as schools or community halls in normal times.

• It trained community volunteers and built early warning systems that reach down to the village.

• Why it matters: this model explains why later Odisha cyclones (Phailin 2013, Fani 2019) caused far fewer deaths.

2. Cyclone Ockhi (2017): danger at sea

• Track: it formed close to Sri Lanka in late November 2017. It then moved west into the Comorin area (the sea south of Kanyakumari) and the Lakshadweep Sea.
• Rapid intensification: it grew from a deep depression into a cyclonic storm within about six hours after coming out from near Sri Lanka [3].
• Areas hit: it affected the coasts of Kerala, Tamil Nadu (Kanyakumari) and Lakshadweep on 29 November 2017 [3].
• Cause → result
• The ocean surface held a lot of heat → this gave the storm extra energy → it strengthened faster than models expected [3].
• IMD did issue an advisory, but it did not warn of an impending cyclone [3].

• Fishermen were already far out at sea → many were killed or went missing.

• Recommendations of the Parliamentary Standing Committee [3]:

• Build forecasting models for rapid intensification, using satellite sea surface temperature data.
• Install satellite-based tracking on all deep-sea fishing boats.
• Raise aid to the families of the dead from ₹2 lakh to ₹5 lakh.

• Change the Centre–state cost-sharing for disaster funds from 75:25 to 90:10.

• Lesson: early warning must reach fishermen already at sea, not only people on the coast.

3. Cyclone Fani (2019): the preparedness model

• Landfall: an extremely severe cyclonic storm that crossed the coast near Puri, Odisha, on 3 May 2019 (NCERT Class 7, Fig. 3.13).
• Why it was unusual
• It was a pre-monsoon (April–May) storm. Bay storms this strong are more common in October–November.

• Very warm Bay waters in summer fed it for a long time over the sea.

• Response

• IMD gave accurate track and landfall forecasts several days ahead.
• Odisha evacuated over a million people (NCERT). The government moved about 1.2 million people into nearly 4,000 shelters before landfall [4].

• Deaths were kept to a few dozen.

• Recognition: the UN Office for Disaster Risk Reduction (UNDRR) praised Odisha's early warning and quick action for saving lives [4].

• The cost: losses to power lines, houses, trees and Puri's coast and town were still huge. Saving lives does not mean saving property.

4. Cyclone Amphan (2020): the super cyclone of the lockdown

• Birth
• It began as a low-pressure area over the south Andaman Sea and southeast Bay of Bengal on 13 May 2020 [2].

• It became a depression near 10.4°N, 87.0°E on 16 May 2020 [2].

• Rapid intensification

• Winds rose from 50 knots to 130 knots between 17 May and late on 18 May. That is about 2.3 times in about a day and a half [2].
• It became a Super Cyclonic Storm around noon on 18 May 2020 [2].

• Causes [2]:

  • low vertical wind shear (little change in wind speed or direction with height, so the storm column stays upright): 10–15 knots
  • very warm sea, with sea surface temperatures of 30–31°C
  • high ocean heat content: 100–120 kJ/cm²

• Peak: winds of 240–250 km/h gusting to 275 km/h, and a lowest central pressure of 920 hPa, over the west-central Bay [2].

• Record: it was the first super cyclonic storm over the Bay of Bengal since the Odisha super cyclone of 1999 [2].
• Landfall
• It crossed the West Bengal–Bangladesh coast across the Sundarbans near 21.65°N, 88.3°E, between 3:30 and 5:30 pm IST on 20 May 2020 [2].
• By then it had weakened to a VSCS, with winds of 155–165 km/h gusting to 185 km/h [2].

• It then passed very close to Kolkata. Dum Dum recorded winds of 130 km/h [2].

• Storm surge: a surge of up to 4.6 m flooded low-lying parts of South and North 24 Parganas and East Medinipur districts of West Bengal [2].

• Track: a clockwise, recurving path about 1,765 km long. It went first north-northwest, then north-northeast [2].
• Forecast skill: at 48 hours before landfall, the forecast landfall point was off by only 11 km. The 2015–19 average error was 69.4 km [2].
• Warnings: IMD used a four-stage warning system:
• Pre-cyclone Watch: 104 hours before landfall
• Cyclone Watch
• Cyclone Alert (yellow)
• Cyclone Warning (orange): 56 hours before landfall

INCOIS also sent about 75 lakh SMS to registered users, including fishermen, and sent bulletins through NavIC to boats at sea [2].

• Special problems
• It hit during the COVID-19 lockdown, so shelters had to keep people apart and fewer people could fit in each.

• It was among the costliest cyclones of the north Indian Ocean.

• Role of mangroves: the Sundarbans mangroves (the world's largest mangrove forest, in the Ganga–Brahmaputra delta, shared by India and Bangladesh) slowed the wind and broke up the surge. This protected the land behind them.

5. Cyclone Biparjoy (2023): a long-lived Arabian Sea storm

• Sea and life span: it formed in the Arabian Sea in June 2023 and lasted about 13 days, which is very long for a north Indian Ocean cyclone.
• Landfall: near Jakhau port, Kachchh district, Gujarat, on 15 June 2023.
• Peak: it reached extremely severe cyclonic storm strength over the sea.
• Why it lasted so long: it moved slowly over a warm sea → it kept drawing heat and moisture → it stayed strong for days before turning towards Kachchh.
• Response: Gujarat followed a "zero casualty" approach. It held large-scale evacuations from the coastal belt ahead of landfall, and deaths stayed very low.
• Significance: it shows that the Arabian Sea is becoming more active, and that Gujarat's west coast now needs Odisha-style preparedness.

6. The overall trend

• Deaths have fallen sharply: about 10,000 deaths in 1999 against a few dozen or fewer in Fani 2019 and Biparjoy 2023.
• Why: better forecasts (satellites, Doppler Weather Radars, ocean data from INCOIS) → earlier warnings → mass evacuation to shelters.
• What has not improved: damage to property (power, housing, crops, fishing boats, coastal towns) is still huge. Fast-forming storms like Ockhi still catch people out at sea.

Prelims Hooks

• First state disaster management authority in India: OSDMA (Odisha, 1999), set up after the Paradip super cyclone.
• Amphan (2020) was the first super cyclonic storm in the Bay of Bengal since 1999 [2].
• Landfall matching:
• 1999 super cyclone → Paradip
• Fani → Puri
• Amphan → Sundarbans (West Bengal–Bangladesh)

• Biparjoy → Jakhau, Kachchh

• Sea matching: Fani and Amphan formed in the Bay of Bengal. Biparjoy formed in the Arabian Sea. Ockhi formed near Sri Lanka and moved into the Lakshadweep Sea.

• Trap: Ockhi did not make landfall on the Indian mainland. It still hit Kerala, Tamil Nadu and Lakshadweep [3].
• Season trap: both Fani (May 2019) and Amphan (May 2020) were pre-monsoon storms, not post-monsoon ones.
• Order of landfall sites, west to east: Jakhau (Gujarat) → Puri (Odisha) → Paradip (Odisha) → Sundarbans (West Bengal).
• Amphan's peak: 240–250 km/h with a central pressure of 920 hPa [2]. Amphan's surge: about 4.6 m in the 24 Parganas [2].
• Factors that drive rapid intensification: low vertical wind shear, sea surface temperatures of 30°C or more, and high ocean heat content [2][3].
• Fani's evacuation: about 1.2 million people were moved into nearly 4,000 shelters, and UNDRR praised the effort [4].

Mains Points

• From reaction to preparedness (GS-III, disaster management)
• Odisha's path from 1999 to 2019 shows how institutions (OSDMA), physical structures (multipurpose shelters), people (community volunteers) and science (IMD forecasts) work together.

• Together they brought deaths down from about 10,000 to a few dozen. Gujarat's "zero casualty" response to Biparjoy (2023) shows that this model can be copied.

• New hazards from a warming sea (GS-I and GS-III)

• Warmer seas and more ocean heat bring rapid intensification (Ockhi, Amphan) [2][3] and longer-lived Arabian Sea cyclones (Biparjoy).

• This shortens warning time. It also exposes the west coast, which has had less experience of cyclones.

• The gap at sea and in property losses

• Ockhi showed that warnings fail fishermen already at sea. The fixes include satellite vessel tracking, NavIC messages and better rapid-intensification models [2][3].

• Property losses, as in Amphan's hit on Kolkata and the Sundarbans, call for cyclone-resistant housing, underground power lines and insurance.

• Nature-based defences

• Sundarbans mangroves reduced Amphan's surge. Mangroves and coastal shelterbelts should be part of coastal zone planning, alongside engineering works like embankments.