4.3. Cyclones

4.3.1 General Information

‘As the cyclones evolve from a loosely organized state into mature, intense storms, they pass through several characteristic stages. The four important stages of storm development were defined as, tropical disturbance, tropical depression, tropical storm and hurricane. There are some variations in the definition and names of these stages of storm’s intensity in one region to other. In the North Indian Ocean, these stages are divided into six categories depending on the maximum sustained surface winds associated with the system. These are given in the following table (IMD Classification):

 

…Roughly 7% of the total global genesis of tropical cyclones occurs in the North Indian Ocean. The average number of tropical cyclones is about 5.6 with standard deviation of 1.85. About 6 tropical disturbances reach tropical storm intensity in the region each year with variations from 1 to 10 during the past 104 years (1891 – 1994). These form from cyclonic disturbances (depressions and deep-depressions) whose annual frequency is about 15.7 with a standard deviation of 3.1. Roughly 35% of these initial disturbances reach tropical storm strength while 45% of these tropical storms reach the hurricane stage. There are 5-6 times more tropical disturbances in the Bay of Bengal than in the Arabian Sea.

The tropical cyclogenesis is highly seasonal in the region. The number reaching tropical storm intensity has a bi-model distribution with the primary maximum in November and a secondary maximum in May. Between these periods, there is a relatively suppressed period of activity. Although rare, storms do occur from January through March.

The India Meteorological Department (IMD) has records since 1877 of the tracks of cyclones and statistics of the frequency of formation and movement in various parts of the basin. It has published the Storm Atlas “Tracks of Storms and Depressions 1891 -1970”. The tracks of storms and depressions subsequent to the year 1970 are published periodically by IMD in its quarterly journal ‘Mausam’.

A large number of studies are available on the cyclone frequency and probability of their crossing the coast in the Indian region. Raghavendra (1973) carried out a statistical analysis of the number of tropical cyclones and Depressions in the Bay of Bengal for the period 1890 – 1969. Mooley and Mohile (1983) studied cyclone incidence on different sections of the coast around Bay of Bengal. Mandal (1991) gave the district-wise frequency of cyclones crossing the east and west coasts. Ramasastry (1984) presented statistics of distribution of number of cyclones affecting the Bay of Bengal and the Arabian Sea.’ (Akhilesh Gupta, ‘Tropical Cyclone in Indian Seas: Observations and Prediction” in ‘Cyclone Disaster Management’ National Interactive Workshop held at Tamil Nadu Agricultural University, February 25-26, 2002. p.21-24)

 

 

Details of various types of wind systems that formed in the Bay of Bengal and affected the east coast of India during the period 1891–2000. (Antonio Mescarenhas, ‘Oceanographic validity of buffer zones for the East Coast of India: A hydrometeorological perspective’ in Curr. Sci., Vol.86, No.3, 10 February 2004, p-400)

 

Type of disturbance	Cyclonic disturbance	Depression/deep depression	Cyclonic storm	Severe cyclonic storm
Number	1087	635	279	173
Maximum (1891–1991)	158 (Aug.)	131 (Aug.)	51 (Oct.)	38 (Nov.)
Minimum (1891–1991)	4 (Feb.)	1 (Mar.)	0 (Feb.)	1 (Jan.)
Yearly average	10	6	3	1.5
Per cent of total	–	58	26	16
Wind speed (km/h)	31–118	31–61	61–88	88–118

 

‘A total of 440 (452 in 1891-2000) cyclones formed in the Bay of Bengal during the period of 104 years (1891-1994). Out of these 440 cyclones, 256 (58%) have crossed India, 68 (15.5%) Bangladesh, 33(7.5%) Myanmar, 5(1%) Sri Lanka and as many as 78 (around 18%) weakened or dissipated over the sea area before making landfall on any of the above countries.

There were a total of 103 Very Severe Cyclonic Storms (VSCS V_max>118kmph) during the above period, roughly one fourth of the total number of cyclones in the Bay of Bengal. About 52% (54) crossed Indian Coast, 25% (26) Bangladesh, 10% (10) Myanmar, 1% (1) Sri Lanka and 12% (12) weakened or dissipated over the sea.

Out of the 256 cyclones which crossed the Indian coast during 1891-1994 period, Orissa has the largest share of 94 cyclones (37%) followed by Andhra Pradesh 65 (25%), West Bengal 49 (19%) and Tamil Nadu 48 (19%). However, out of the total 54 hurricanes (VSCS) which crossed the Indian coast, West Bengal has the highest number of VSCS i.e 16 (30%) followed by Andhra Pradesh 15 (28%), Orissa 14 (26%) and Tamil Nadu 9 (16.5%).

No cyclones cross the coastal states of West Bengal, Orissa and Andhra Pradesh during January to March and West Bengal and Orissa coasts in April. On the other hand, Tamil Nadu has zero frequency in March and during the south west monsoon months of June to September. Orissa doesnot have any cyclone in December. West Bengal has the highest frequency during July and August. Andhra Pradesh shows very high frequency of 20-25 cyclones during the months of October and November whereas Tamil Nadu has the highest frequency of 27 cyclones in the month of November.

West Bengal has 1% probability of 5 or more cyclones in a year, whereas Orissa has the same probability (1%) for 4 or more cyclones in a year. The east coast as a whole, however, has 1% probability of 7 or more cyclones crossing in a year. In fact 1943 is the only year during the above said 104 years in which 7 cyclones crossed the east coast, 3 in Orissa and 2 each in Andhra Pradesh and Tamil Nadu. Orissa has the highest probability (56%) of at least one cyclone. Andhra Pradesh, West Bengal and Tamil Nadu have respectively 46%, 36% and 27.5% probabilities of atleast one cyclone making landfall per year. There is 98% probability that atleast one cyclone will cross the eat coast of India. It may be mentioned that 1920, 1965 and 1975 were the three years during which not a single cyclone crossed the east coast of India. (Akhilesh Gupta, ‘Tropical Cyclone in Indian Seas: Observations and Prediction” in ‘Cyclone Disaster Management’ National Interactive Workshop held at Tamil Nadu Agricultural University, February 25-26, 2002. p.21-26)

 

4.3.2. Attributes of a Cyclone

“A cyclone causes damage in three ways:

1. The storm surge which is an abnormal rise of sea level causing inundation of the coastal areas.

2. Very strong winds that damage buildings and other structures.

3. Heavy rain that causes floods, as well as erosion of structures.” 

(S.Raghavan, “The May 1990 cyclone and its predecessors” in Journal of Applied Hydrology, Vol.IV, No.1&2, 1991. p-1)

 

4.4.3. Classification of the East Coast of India based on Storm Surge values

‘Apart from the cyclone characteristics like its intensity, time of landfall, speed of movement, angle at which it strikes the coast, etc., the peak surge over an area mainly depends on the coastal structure known as bathymetry.

By the considerations of past recorded surge values, the entire East Coast of India can be classified into four main coastal stretches which are highly prone to surges due to cyclones of the Bay of Bengal.

The first area of importance is the coastal area of Bengal and Bangladesh in the head Bay of Bengal. Some of the noteworthy storms, which caused phenomena storm surge s of the order of ascent 13 meters, were reported only in this stretch. The second vulnerable area is the coastal stretch between Paradeep and Balassore in Orissa where storm surges of the range 5 meters to 7 meters were reported on many occasions. In the case of the False Point (Orissa) cyclone of 22^nd September 1885 a surge of 8 meters was reported at several places. The third area is the coastal stretch between South of Masulipatnam and Kakinada in Andhra Pradesh. The frequency incidence of storm surge is highest in this stretch, where surge height ranges between 5 meters and 7 meters. The area particularly between Coringa and Masulipatnam gets inundated repeatedly and several structures were rebuilt several times.

As regards Tamil Nadu, the coastal area south of 10⁰N between Pamban and Nagapattinam is highly vulnerable to storm surges and this stretch has also experienced storm surges of the range 3 m to 5m on several occasions. The 23^rd December 1964 storm is a typical example, when a storm surge of height reaching 5 meters washed away the entire Dhanushkodi Island and the Pamban Bridge.

The west coast of India is almost free from disastrous storm surges. Historic records however show that surges are frequent in Gujarat coast where astronomical tides are quite high and the surge heights are of the order 2-3m. Only a very few incidences of storm surges was reported around Bombay area and near Honavar. Kerala and Goa coasts are almost free of storm surge.

Thus, based on the details of peak storm surge, the entire Indian coast can be categorized into four zones:

1) Very high risk prone (surge heights greater than 5 meters),

2) High risk prone (surge heights between 3 to 5meters),

3) Moderate risk prone (surge height rising between 1.5 m and 3 m), and

4) Minimal risk prone (surge height less than 1.5 m).

Coastal areas of Bangladesh, North Orissa and West Bengal are the most vulnerable zones to storm surges of height greater than 5 m and so also is the Krishna estuary in Andhra Pradesh. South Orissa, north coastal Andhra Pradesh, South Tamil Nadu are areas where surge height between 3 m to 5 m can be expected. Only Saurashtra Kutch coast is vulnerable to storm surges of height 3 m. Kerala, South Karnataka, Goa coasts are the minimal surge prone zones recording less than 1.5 meters. ( N.Jeyanthi, “Cyclone Disaster Risk in Coastal Region”, in ‘Cyclone Disaster Management’ National Interactive Workshop held at Tamil Nadu Agricultural University, February 25-26, 2002. p.54-55)

 

Location, maximum wind speed, observed height of associated storm surges and actual inland penetration of sea water during some severe tropical cyclonic events that affected the east coast of India.  (Antonio Mescarenhas, ‘Oceanographic validity of buffer zones for the East Coast of India: A hydrometeorological perspective’ in Curr. Sci., Vol.86, No.3, 10 February 2004, p-400)

 

 

Period	Coast affected	Max. wind speed (km/h)	Max.surge height (m)	Hinterland inundation (km)
October 1737	Hoogly river, W.B	272	12.1	100
May 1823	Balasore, Orissa	–	–	10
November 1867	East of Calcutta, W.B	60	1.8	–
October 1942	Medinipur, West Bengal	–	5.0	40
October 1949	Masulipatnam–Kakinada, A.P.	137	4.5	15
November 1952	Nagapatnam, T.N	88	1.2	8
October 1955	Kalingapatnam, A.P.	111	1.5	–
November 1955	Rajamadam, T.N.	193	4.5	16
December 1955	Tanjore, T.N	200	5.0	3–8
October 1963	Cuddalore, T.N.	139	6.0	–
December 1964	Rameshwaram, T.N	278	6.0	–
October 1971	Paradip, Orissa	170	6.0	10–25
November 1973	North of Paradip, Orissa	137	4.5	–
August 1974	Contai, West Bengal	139	3.0	–
September 1976	Contai, West Bengal	160	3.0	–
November 1977	Nizampatnam, A.P.	193	5.0	8–15
November 1977	Divi–Machilipatnam, A.P.	120	5.0	12
November 1978	Ramanathpuram, A.P.	204	5.0	–
May 1979	South of Ongole, A.P.	160	3.6	–
November 1989	Near Kavali, southern A.P.	222	4.0	1–2
May 1990	Nellore, A.P.	102	5.0	16
November 1991	Karaikal, T.N.	89	–	< 1
November 1992	Tuticorin, T.N.	113	1.0	–
December 1993	Karaikal, T.N.	133	4.0	2
October 1999	Paradip/Balasore, Orissa	252	9.0	35

 

 

 

 

 

4.4.4. Consequences due to Cyclonic disturbances

 

Modifications of coastal landforms by cyclones

Severe cyclonic events are responsible for dramatic modifications of the landscape. The cyclone of October 1999 resulted in heavy sedimentation near the coast of Orissa; the receding waters brought additional silt. Extreme events result in severe shoreline changes and hence affect coastline configuration: beach and dune erosion, modifications of dune complexes, dune breaching, over wash, inlet formation and, at places, complete elimination of sand-dune complexes is documented. In West Bengal, more and more land is being eroded following violent storms.

 

Effect on ports and fishing harbors

In November 1966, a tidal bore battered Madras port. Tuticorin harbor was directly hit in November 1992; breakwater and pier heads were damaged. Harbors were paralyzed along Digha–Haldia sector in August 1997. Minor ports of Machilipatnam and Krishna delta were affected in November 1977, and trawlers got drowned in Haldia in August 1997 . Should a seaport be shut down, as witnessed at Paradip in October 1999, the overall losses are beyond contemplation.

 

 (Antonio Mescarenhas, ‘Oceanographic validity of buffer zones for the East Coast of India: A hydrometeorological perspective’ in Curr. Sci., Vol.86, No.3, 10 February 2004, p-400 -401)

 

Location and impact of some severe cyclones that affected Indian coasts during the last 25 years.

 

Period	Location	Impact/Damage
19 Nov. 1977 .	Divi, Krishna River delta, A.P	10,000 lives lost; standing crops washed away; persistent flooding even 11 days after the cyclone struck.
27–29 May 1989	24 Parganas/Medinipur, W.B.	485 lives lost; 2,02,468 houses damaged; standing crops                                                                                                   washed away; 239 km of protective works destroyed; dune barrier breached.
4–10 May 1990	Machilipatnam, mouth of River Krishna,A.P	967 deaths; 6,00,000 houses destroyed; 21,600 cattle,                                   3 5,00,000 poultry, 42,700 goats perished, damage to agriculture.
11–17 Nov. 1992	Tuticorin, T.N.	170 killed; 160 missing; 1 to 2 m storm surge at Tuticorin.
1–4 Dec. 1993	Near Karaikal, T.N.	111 killed; 1 to 1.5 m storm surge.
29–31 Oct. 1994	Chennai and around, T.N.	304 killed; 1 to 2 m storm surge; 1,00,000 huts destroyed;  60,000 hectares of crops damaged.
7–10 Nov. 1995	Gopalpur, Orissa	96 killed; 1.5 m surge; 2,84,253 hectares of crops damaged.
5–7 Nov. 1996	Kakinada, A.P.	978 killed; 2 to 3 m surge; 1375 missing; 6,47,554 houses  damaged; 1,74,000 hectares of crops damaged.
22–24 August 1997	Digha–Haldia, West Bengal	400 fishermen missing; 1,60,400 people homeless; coastal hotels inundated; 40 trawlers drowned; 10,000 houses destroyed; over 600 m of seawalls and embankments devastated; prawn hatcheries swept away; harbors paralyzed.
29–31 Oct. 1999	Balasore/Paradip, Orissa Super Cyclone	7–9 m surge; inundations up to 35 km from coast; 9885 persons died; 2142 people injured; 12 lakh houses damaged;  over 2 lakh cattle killed; 13 lakh hectares of crops affected;  port activity paralyzed.

 

4.3.5. Frequency and Intensity of the Cyclones of Bay of Bengal – The changing scenario

 

‘Observational records suggest that, while there has been a rising trend in all-India mean surface air temperature, the number of monsoon depressions and tropical cyclones forming over the Bay of Bengal and Arabian Sea exhibits declining trend since 1970. There have been a number of studies that have considered likely changes in tropical cyclones in a warmer atmosphere. Some recent global climate model experiments suggest a future decline in tropical cyclone frequency1. Jones et al.performed an analysis of tropical cyclones from a 140-year simulation with regional climate model (RCM) nested in A–O GCM. This analysis indicated that there was a small decrease in tropical cyclone formation, although this result is considered preliminary. The pattern of cyclones during phases of ENSO (El Nino – Southern Oscillation) was unchanged, suggesting that the current relationship between cyclone distribution and ENSO may continue. This study, however, reconfirmed an increase in cyclone intensity (10–20%) with CO2-induced warming as estimated by Tonkin et al. and Holland as being likely.

 

Although no consensus has emerged as yet on the behavior of tropical cyclones in a warmer world based on modeling studies, it is almost certain that an increase in SST will be accompanied by a corresponding increase in cyclone intensity (wind speed). The relationship between cyclone intensity (maximum sustained wind speed) and SST is well discussed in literature. A possible increase in cyclone intensity of 10–20% for a rise in SST of 2 to 4°C relative to the threshold temperature of 28°C is very likely. Thus, while it is not yet certain that tropical cyclone frequency may change the available data strongly suggest that an increase in its intensity is most probable.

 

Storm surges are generated by the winds and the atmospheric pressure changes associated with cyclones. At low latitude land-locked locations such as the Bay of Bengal, the tropical cyclones are the major cause of storm surges. Any increase in SST is likely to cause greater convective activity, leading to an increase in wind speed. The stress exerted by wind on water underneath is proportional to the square of the wind velocity. Amplification in storm surge heights should result from the occurrence of stronger winds and low pressures associated with tropical storms. Thus, an increase in SST due to climate change should lead to higher storm surges and an enhanced risk of coastal disasters along the east coast of India.’ (M.Lal, ‘Tropical cyclones in a warmer world’, in CURRENT SCIENCE, VOL. 80, NO. 9, 10 MAY 2001, p-1103-1104)

 

4.3.6. Coasts most vulnerable for severe Tropical Cyclone – Recent statistical elucidation

 

‘Among the different segments of Bay (of Bengal) coast under consideration (East Sri Lanka, Arakan (Burma), Tamil Nadu, Bangladesh, Andhra Pradesh, Oriss – West Bengal), the coasts of Tamil Nadu and Bangladesh are most vulnerable for Severe Tropical Cyclones as the anticipation of occurrence of such weather calamities are difficult over these two coasts.’ (Sutapa Chaudhuri, Surajit Chattopadhyay, ‘Identification of coasts vulnerable for severe Tropical Cyclones – Statistical Evaluation’ in Mausam, 55, 3 (July 2004), p-507). 

 

 

 

4.3.7. Tamil Nadu Data

Frequency distribution of the cyclones over the coastal districts of Tamil Nadu 1891-1995

 

District	Number of Cyclones
Chengalpattu including Chennai	21
S.Arcot including Pondicherry	13
Thanjavur including Pudukottai	14
Ramanathapuram	6
Tirunelveli	3
Kanyakumari	4
Total	61

 

The month wise frequency of cyclonic storms that crossed the Tamil Nadu coast during the period 1891 – 2000

CS – Cyclonic Storm                SCS – Severe Cyclonic Storm

 

Month	Frequency CS	Frequency SCS	% of SCS out of total cyclone
January	3	1	33
February	1	1	100
March	1	-	0
April	2	1	50
May	3	1	33
June	-	-	-
July	-	-	-
August	-	-	-
September	-	-	-
October	6	2	33
November	34	22	64
December	14	8	57
Annual	64	36	55

  (Ref: N.Jeyanthi, “Cyclone Disaster Risk in Coastal Region”, in ‘Cyclone Disaster Management’ National Interactive Workshop held at Tamil Nadu Agricultural University, February 25-26, 2002. p.51-54).

 

 

4.4.8. Cyclones of Palk Bay – some examples

 

1. Severe cyclonic storm of 17 – 24 November, 1978:

 

‘Under the influence of a low pressure area moving westwards across Malaya Peninsula and south Andaman Sea, a low which lay over southeast Bay concentrated into a depression on the morning of 17^th with its centre near 6.5⁰N, 91⁰E. Moving slowly northwards, it intensified into a cyclonic storm near 8⁰N, 91⁰E on the morning of 20^th as identified by the satellite pictures. A dim ‘eye’ was also noticed by the satellite. It developed a core of hurricane winds by the morning of 21^st when it was centered near 7.5⁰N, 88.5⁰E. The storm progressively intensified further and took a west-south-westerly and later a north-westerly course and crossed Sri Lanka coast on 23^rd night near Batticola. According to satellite pictures the storm reached its peak intensity on 23^rd morning when the estimated maximum winds were 120 kt (222.24 kmph). The storm retained the hurricane intensity even over land, till it emerged into Gulf of Mannar. It moved south of Pamban and crossed Tamil Nadu coast between Kilakkari and Roche Mary Nagar in Ramanathapuram district on 24^th evening as a severestorm and emerged into the Arabian Sea off Kerala coast as a deep depression on 25^th morning.

 

Tidal waves of 3-5 meters affected the Rameshwaram Island and the coastal areas of Ramanathapuram district between Tondi and Devipattinam. According to press reports and information obtained from State Govt., the coastal taluks, namely Ramanathapuram, Tiruvadanai, Mudukulathur and Rameshwaram of Ramanathapuram district were worst affected by the cyclone.

 

About 5,000 huts were damaged in these taluks. A large number of trees were uprooted. About 1,000 country boats and mechanized fishing vessels were damaged in Rameshwaram, Pamban, Kilakkarai, Mandapam, Vedalai and Morepannai areas. Boat building yards at Mandapam and Morepannai were also damaged. Materials and machinery stored for construction of road bridge near Pamban were washed away. There was also extensive damage to roads in Ramanathapuram district due to heavy rain. Crops of sugarcane, chillies, betel vines and plantain were also damaged in the interior taluks of Sattur, Paramakkudi, Aruppukkottai, Srivilliputtur, Rajapalayam and Virudhunagar. The total damage to property was estimated to be about 5 crores of rupees. Thanjavur and Thirunelveli districts also suffered some damage to roads. Road and rail communications were disrupted in southern Tamil Nadu.

 

As reported in the press, this storm was the worst to hit Sri Lanka in the last half a century. The toll of human lives in Sri Lanka was estimated to be about one thousand. Serious loss to property was also reported.’ (V.Srinivasan, A.R.Ramakrishnan and R.J.Jambunathan, ‘Cyclones and depressions in the Indian seas in 1978’, in Mausam, (1980), 31, p.501-502)

 

2. Deep Depression of 13 – 15 December, 1973.

 

‘A low pressure area formed over extreme south east Bay on 10^th and became well marked on the 11^th and 12^th. It concentrated into a depression at 1200 GMT of 13^th near 7⁰N, 88.5⁰E. Moving west-north-west, it became deep on the morning of 14^th with its centre near 8⁰N, 85⁰E. Continuing to move west-north-west, it crossed south Tamil Nadu coast near Pamban on 15^th night and emerged into Lakshadweep – Maldive area on 16^th as a low.

 

In association with this system, fairly widespread rain with isolated heavy falls occurred in Tamil Nadu from 15^th to 17^th.’ (George Alexander, C.A.George and R.Jambunathan, ‘Cyclones and depressions of 1973 – Bay of Bengal and Arabian Sea’, in Indian Journal of Meteorology and Geophysics, July & Oct., 1974, Vol.25 Nos. 3&4. p-357-358)

 

3. Depression of 2-4 December, 1982

 

A low which lay over southeast Bay on 1^st, moved westwards and concentrated into a depression over southwest Bay by 2^nd evening centered at 1200 GMT near 7.5⁰N, 84.0⁰E. Thereafter moving initially northwestwards and then west-northwestwards it crossed Tamil Nadu coast near Tondi in the morning of 4^th and weakened over land. This system caused generally widespread rain/ thunderstorm in Tamil Nadu and Kerala on 4^th with isolated heavy to very heavy falls in Tamil Nadu. (A.A.Ramasastry, A.K.Chaudury, and N.C.Biswas, ‘Cyclones and depressions over the Indian seas in 1982’, in Mausam, (1984), 35, 1, p.7)

 

4. Nagapattinam Cyclone of 8-12 November, 1977

 

A low pressure area moved westward across south Andaman Sea into southeat Bay on the morning of 8^th November and concentrated into a depression on that evening with its center near 8⁰N, 92⁰E. Moving northwestwards initiall and later in a westerly direction, the depression intensified into a cyclonic storm on the morning of 10^th and into a severe cyclonic storm on the morning of 11^th when it was centered near 11.⁰N, 82.5⁰E. The storm crossed Tamil Nadu coast within 10 km to south of Nagapattinam in the early morning of 12^th (around 2230 GMT of 11^th). It weakened into a cyclonic storm by that evening over interior parts of Tamil Nadu and emerged into Lakshadweep off nort Kerala coast on the morning of 13^th as a deep depression.

 

This system caused generally widespread rain in Andaman and Nicobar Islands from 8^th to 10^th and in Tamil Nadu and Rayalseema on 12^th and 13^th with heavy to very heavy falls in Tamil Nadu on 12^th and 13^th and in Kerala on 13^th… Gales reaching about 120 kmph lashed Thanjavur, Trichy and Pudukottai districts uprooting many trees. Electric and telegraph posts were bent and twisted in Thanjavur district, the worst affected taluksbeing Nagapattinam, Mannargudi and Thiruthuraipoondi. Roofs of pucca buildings were blown off in these areas. Madurai, Pudukottai and Trichy districts were worst affected by floods.

 

No tidal waves were associated with this storm.

 

(P.S.Pant, A.R.Ramakrishnan and R.Jambunathan, ‘Cyclones and depressions over the Indian seas in 1977’, in Mausam, (1980), 31, 3, 343-344).

 

4.4.9. Miscellaneous information on some Palk Bay Cyclones

 

‘ During 1960’s the fishermen of Palk Bay region bitterly complained about the disappearance of large beds of algae owing to the cyclone in 1964, and turtles and dugongs almost disappeared in this area. Fishermen now report that the algal beds have sprung up once again (i.e. after almost 20 years)’. (NEERI EIA, p-3.63)

 

‘Cyclones have sustained winds with speed ranging from 65 to 120 kmph. High speed winds cause extreme wave action that break coral into rubbles and sometimes large amounts of sand and other materials may be dumped onto the coral reef. Due to 1969 cyclone a large area of coaral was buried under the sand in Rameshwaram area of Gulf of Mannar.’ (NEERI EIA, p-3.67).

 

“The Dutch records of April 1627 tells us of a great storm that had occurred a month earlier on the southern and central sections of Coromandel, in which vessels from Sao Tome (now Chennai), Covelong, Porto Novo, Karaikal, Thirumullaivasal and Nagapattinam capsized in substantial numbers; the losses were estimated at over two hundred vessels, and bodies, timber and goods were washed ashore for days afterwards.” (Quoted from ‘Algemeen Rijksarchief, The Hague .Overgekomen Brieven en Papieren .Verenigde Oost-Indische Compagnie. 1085. Dagh-Register op’t Cust, 9/4/1626 – 17/9/1628, fls.37v-38’ by Sanjay Subrahmanyam in “The Political economy of commerce: southern India, 1500-1650”, Cambridge University Press, 1990, p-49)