Cyclone Mandous, a severe cyclonic storm in the Bay of Bengal, is likely to bring heavy rainfall to parts of Tamil Nadu.

 

What are ‘cyclones’?

  • Cyclones are known as typhoons in the China Sea and Pacific Ocean; hurricanes in the Caribbean Sea and Atlantic Ocean; tornados in the Guinea lands of West Africa and southern USA; willy-willies in north-western Australia and tropical cyclones in the Indian Ocean.
  • Cyclones are caused by atmospheric disturbances around a low-pressure area distinguished by swift and often destructive air circulation.
  • Cyclones are usually accompanied by violent storms and bad weather.
  • The air circulates inward in an anticlockwise direction in the Northern hemisphere and clockwise in the Southern hemisphere.

 

Types

  • Cyclones are classified as —
    • extra tropical cyclones; and
    • tropical cyclones.
  • According to the World Meteorological Organisation (WMO), ‘Tropical Cyclone’ covers weather systems in which winds exceed ‘Gale Force’ (minimum of 34 knots or 63 kph).
  • Extra tropical cyclones (also called temperate cyclones) occur in temperate zones and high latitude regions, though they are known to originate in the Polar Regions.