It is raining ! Simple, remain at home, do not venture out !!
Chennaites are under difficult times ! – it has been raining as Cyclone Fengal moves closer to the Tamil Nadu coast. Rains are not new ! – perhaps Storms, Cyclone too are not new !! Cometh Nov – Dec, we hear one name after the other of impending Cyclones – sometimes, Orange, Red alerts turn into nothing !! with weather bloggers predicting cloud burst, very heavy rain, inundation and mugger crocs out there on streets !!!
Deep Depression over Southwest Bay of Bengal intensified into Cyclonic Storm “FENGAL” [pronounced as FEINJAL]. The Cyclonic Storm “FENGAL” moved west-northwestwards with a speed of 13 kmph during past 6 hours and lay centred at 0830 hours IST of today, the 30th November 2024 over the same region near latitude 12.3°N and longitude 80.9°E, about 120 km east-northeast of Puducherry, 110 km southeast of Chennai, 200 km north-northeast of Nagappattinam and 420 km north of Trincomalee. It is likely to move nearly westwards and cross north Tamil Nadu-Puducherry coasts between Karaikal and Mahabalipuram close to Puducherry as a cyclonic storm with a wind speed of 70-80 kmph gusting to 90 kmph during evening of 30th November says IMD Bulletin.
In recent decades, as an Insurer, have experienced many storms, cyclones, heavy rains, inundation and more. In school days, remember 1977 was a bad year – Kotturpuram was badly affected.
Nov 1977 was at its worst. In mid Nov, a devastating tropical cyclone hit Andhra Pradesh reported killing around 10,000 people. The worst affected areas were in the Krishna River delta region. The island of Diviseema, was hit by a seven-metre-high (20 ft) storm surge, experienced a loss of life running into the thousands. The large loss of life prompted the establishment of early warning meteorological stations on the coast of Andhra Pradesh. Cyclone shelters and other measures for disaster management were also taken. A memorial, at the point of furthest advance of the tidal wave, near the town of Avanigadda, was built in memory of the people who died in the storm.
That year, there were one too many. Between Oct 27 – Nov 1 1977 – a cyclone crossed South Andhra Pradesh coast near Kavali between Nellore and Ongole. Weakened into a depression over the interior parts of Karnataka by morning of November 1 and emerged into the Arabian sea, It caused huge damage to property and Telegraph posts over 80 km stretch from Kavur to singaraykonda about 40 km on either side of the storm track stood slanting. Close on its heels, on Nov 8-12, another struck and crossed Tamilnadu coast within 10 km to south of Nagapattinam early in the morning. The speed of the wind recorded about 120 KMPH ( 65 kt) on 12th mroning at Thanjavur , Tiruchirapalli and Podukottai. 560 people died and 10 lakh people rendered homeless, according to reports. 23,000 Cattle heads perished. Total damage to private and public property was put to be Rs. 155 crores. Then in mid Nov, cyclone made a landfall Chirala in A.P at 1200 UTC on 19th Nov and weakened into a low on the evening of 20th. Maximum wind speed recorded by the ship Jagatswami recorded at 1030 Utc on 17th was 193 KMPH( 104kt). This killed thousands of people, damaged acres of crops and property damage was estimated to be around 350 cr of those days !!!
Here is something extracted from – ‘Handbook of Cyclonic storms in Bay of Bengal’ published for the use of Sailors by John Eliot, MA, FRS, CIE, Director General of Indian Observatories printed in 1900 priced Four rupees.
"On the 2nd of October 1746 the weather at Madras was remarkably fine
and moderate all day. About midnight a furious storm arose and continued with the greatest violence until the noon of the next day. Six of the French ships were in the road when the storm began, and not one of them was seen at day break. One put before the wind and was driven so much to the southward that she was not able to gain the coast again ; the 70-gun ship lost all her masts; three others of the squadron were likewise dismasted, and had so much water in the hold that the people on board expected every minute to perish, notwithstanding they had thrown overboard all the cannon of the lower tier; the other ship, during the few moments of the whirlwind which happened in the most furious part of the storm, was covered by the waves, and foundered in an instant and only six of the crew escaped alive. Twenty other vessels, belonging to different nations, were either driven on shore or perished at sea. Two ships, laden with part of the effects of Madras, together with three lately arrived from Europe, were at anchor in the road of Pondicherry, where they felt no effect of the storm which was raging at Madras.'
Three years later, in the evening of the 13th of April 1749 the northern monsoon changed, and the southern commenced with a hurricane on the Coromandel Coast. At Portonovo it lasted with such violence until four o'clock the next morning that the tents of the English forces which were encamped on the bank of the River Vellar (which disembogues itself at Portonovo) were blown into rags, many of the draught bullocks and horses were killed, and all the military stores were so much damaged that the army was obliged to march to Portonovo, in order to repair the detriments it had sustained. Here they were informed that the storm had committed much greater ravages at sea ; two of the Company's ships were stranded between Cuddalore and Fort Saint David ; the Apollo hospital ship was lost with all her crew; the Pembroke a 60-gun ship, which sailed on the expedition, was wrecked and only six of the crew saved ; and the Hamur of 74 guns, in which Admiral Boscawen hoisted his flag, and which was the finest ship of her size belonging to the navy of England, perished with 750 men. Fortunately most of the other ships were either at Trincomalee, or in parts of the coast to which the greatest violence of the hurricane did not extend."
It is hardly too much to say that the knowledge of the laws of storms, which is due to the labours of meteorologists utilizing the observations furnished by thousands of seamen, is now sufficient, if properly employed, to enable sailors to avoid the full strength of cyclonic storms in the open sea of the Bay of Bengal. Disasters still occasionally happen, and, in some cases at least, may be traced to neglect of the most ordinary precautions, or to disregard of the accumulated experience of the past.
Air motion in cyclonic storms is a complex phenomenon that arises when more or less violent actions occur over an area or center of disturbance. Thus, for example, when a very large forest is on fire, the heated air over it rises and the air flows in towards it from all sides. The air which rises up after it reaches a certain height tends to spread out and to move away in all directions. The inflow near the surface of the earth to the heated air does not take place directly, but by a species of spiral or revolving motion, forming whirls, such as are very common in water motion, even on the smallest scale. The air is in such a motion drawn to to the centre, but not directly. It moves round the center of the disturbance and at the same time moves towards the central area into which it is drawn and passes upwards. Hence, when such a disturbance is started, the air at and near the earth's surface rushes towards the center from all directions, and the actual motion which results from such a rush towards a central area of disturbance and uptake is always rotatory. In the case of very small whirls such as give rise to waterspouts at sea, the whirling or rotatory motion is probably due to the fact that the air from different directions rushes in with slightly different velocities or rates of motion. In the case of the enormous whirls which form cyclonic storms this is not the chief cause in operation. This is due to the fact that the air is connected with the earth, which is a moving body. Hence, when the air is in apparent motion, it is actually moving with respect to a body which is itself in motion.
Interesting – with graphic details taken from - https://mausam.imd.gov.in/imd_latest/contents/cyclone.php
Regards S Sampathkumar
30.11.2024
