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60 INDIA : PHYSICAL ENVIRONMENT (i) Large and continuous supply of warm A surge is generated due to interaction and moist air that can release enormous of air, sea and land. The cyclone provides latent heat. the driving force in the form of very high (ii) Strong Coriolis force that can prevent horizontal pressure-gradient and very filling of low pressure at the centre strong surface winds. The sea water flows across the coast along with strong winds (absence of Coriolis force near the and heavy downpour. equator prohibits the formation of tropical cyclone between 0°-5°° This results in inundation of human latitude). settlements, agricultural fields, damaging (iii) Unstable condition through the crops and destruction of structures created tropospherethatcreateslocaldisturbances by human beings. around which a cyclone develops. (iv) Finally, absence of strong vertical wind Floods wedge, which disturbs the vertical You read in newspapers and watch images of transport of latent heat. floods on televisions occurring in some regions during rainy seasons. Inundation of land and Spatio-temporal Distribution of Tropical human settlements by the rise of water in the Cyclone in India channels and its spill-over presents the Owing to its Peninsular shape surrounded condition of flooding. Unlike other natural disasters, the causes of floods are well- by the Bay of Bengal in the east and the established. Floods are relatively slow in Arabian Sea in the west, the tropical cyclones in India also originate in these occurrences and often, occur in well-identified two important locations. Though most of regions and within expected time in a year. Floods occur commonly when water in the the cyclones originate between 10°-15°° form of surface run-off exceeds the carrying north latitudes during the monsoon capacity of the river channels and streams and season, yet in case of the Bay of Bengal, flows into the neighbouring low-lying flood cyclones mostly develop during the months plains. At times, this even goes beyond the of October and November. Here, they capacity of lakes and other inland water bodies originate between 16°-2°° N latitudes and in which they flow. Floods can also be caused to the west of 92° E. By July the place of duetoastormsurge(inthecoastalareas),high origin of these storms shifts to around 18° N intensity rainfall for a considerably longer time latitude and west of 90°E near the period, melting of ice and snow, reduction in Sunderban Delta. the infiltration rate and presence of eroded material in the water due to higher rate of soil erosion. Though floods occur frequently over Consequences of Tropical Cyclones wide geographical area having disasterous It was mentioned that the energy to the ramificationsinmanypartsoftheworld,floods tropical cyclone comes from the latent heat in the South, Southeast and East Asian released by the warm moist air. Hence, with countries, particularly in China, India and Bangladesh, are frequent and equally the increase in distance from the sea, the forcedisastrous. of the cyclone decreases. In India, the force Once again, unlike other natural disasters, of the cyclone decreases with increase in distance from the Bay of Bengal and the human beings play an important role in the Arabian Sea. So, the coastal areas are often genesis as well as spread of floods. Indiscriminate deforestation, unscientific struck by severe cyclonic storms with an agricultural practices, disturbances along the average velocity of 180 km/h. Often, this natural drainage channels and colonisation results in abnormal rise in the sea level known as Storm Surge. of flood-plains and river-beds are some of the human activities that play an important role 2026-27