Question

why do tropical cyclones cause widespread rain fall in the month of oct and nov in the east coast of india

Answer 1

India is highly vulnerable to natural hazards especially earthquakes, floods, drought, cyclones and landslides. Studies indicate that natural disaster losses equate to up to 2% of India’s Gross Domestic Product (GDP) and up to 12% of Central government revenue. The cyclones that occur between Tropics of Cancer and Capricorn are known as Tropical Cyclones. Tropical cyclones are weather systems in which winds equal or exceed gale force (minimum of 34 knot, i.e., 62 kmph). Indian sub-continent is the worst affected region of the world, having a coast line of 7516 kms. (5400 kms along the mainland, 132 kms in Lakshadweep and 1900 kms in Andaman and Nicobar Islands) is exposed to nearly 10% of the world’s Tropical Cyclones. There are 13 coastal states/UTs encompassing 84 coastal districts which are affected by cyclones (Fig. 1). Four States (Andhra Pradesh, Odisha, Tamil Nadu and West Bengal) and one UT (Pondicherry) on the East Coast and One State (Gujarat) on the West Coast are more vulnerable to cyclone disasters. 40% of the total population lives within 100 km of coastline. Analysed data for the period 1980-2000 shows that on an average, annually 370 million people are exposed to cyclones in India. Cyclones occur in the month of May-June and October-November, with primary peak in November and secondary peak in May. Although cyclones affect the entire coast of India the East Coast is more prone compared to the West Coast. An analysis of the frequencies of cyclones on the East and West coasts of India during 1891-2000 show that nearly 308 cyclones (out of which 103 were severe) affected the East Coast. During the same period 48 tropical cyclones crossed the West Coast, of which 24 were severe cyclonic storms. Out of the cyclones that develop in the Bay of Bengal, over 58 percent approach and cross the East Coast in October and November. Only 25 % of the cyclones that develop over the Arabian Sea approach the West Coast. In the pre-monsoon season, corresponding figures are 25 percent over Arabian sea and 30 percent over Bay of Bengal. Recurring cyclones account for large number of deaths, loss of livelihood opportunities, loss of public and private property and severe damage to infrastructure, thus seriously reversing the developmental gains at regular intervals. Broad scale assessment of population at risk suggests that an estimated 32 crore people, which accounts for almost third of the country’s total population, are vulnerable to cyclone related hazards. Climate change and its resultant sea-level rises can significantly increase the vulnerability of coastal population.

Answer 2

India is highly vulnerable to natural hazards especially earthquakes, floods, drought, cyclones and landslides. Studies indicate that natural disaster losses equate to up to 2% of India’s Gross Domestic Product (GDP) and up to 12% of Central government revenue. The cyclones that occur between Tropics of Cancer and Capricorn are known as Tropical Cyclones. Tropical cyclones are weather systems in which winds equal or exceed gale force (minimum of 34 knot, i.e., 62 kmph). Indian sub-continent is the worst affected region of the world, having a coast line of 7516 kms. (5400 kms along the mainland, 132 kms in Lakshadweep and 1900 kms in Andaman and Nicobar Islands) is exposed to nearly 10% of the world’s Tropical Cyclones. There are 13 coastal states/UTs encompassing 84 coastal districts which are affected by cyclones (Fig. 1). Four States (Andhra Pradesh, Odisha, Tamil Nadu and West Bengal) and one UT (Pondicherry) on the East Coast and One State (Gujarat) on the West Coast are more vulnerable to cyclone disasters. 40% of the total population lives within 100 km of coastline. Analysed data for the period 1980-2000 shows that on an average, annually 370 million people are exposed to cyclones in India. Cyclones occur in the month of May-June and October-November, with primary peak in November and secondary peak in May. Although cyclones affect the entire coast of India the East Coast is more prone compared to the West Coast. An analysis of the frequencies of cyclones on the East and West coasts of India during 1891-2000 show that nearly 308 cyclones (out of which 103 were severe) affected the East Coast. During the same period 48 tropical cyclones crossed the West Coast, of which 24 were severe cyclonic storms. Out of the cyclones that develop in the Bay of Bengal, over 58 percent approach and cross the East Coast in October and November. Only 25 % of the cyclones that develop over the Arabian Sea approach the West Coast. In the pre-monsoon season, corresponding figures are 25 percent over Arabian sea and 30 percent over Bay of Bengal. Recurring cyclones account for large number of deaths, loss of livelihood opportunities, loss of public and private property and severe damage to infrastructure, thus seriously reversing the developmental gains at regular intervals. Broad scale assessment of population at risk suggests that an estimated 32 crore people, which accounts for almost third of the country’s total population, are vulnerable to cyclone related hazards. Climate change and its resultant sea-level rises can significantly increase the vulnerability of coastal population.