Tropical Cyclones

About Cyclone Fani

  • Cyclone Fani (pronounced as Foni) is a pre-monsoon tropical cyclone recently developed over Bay of Bengal.
  • It has been predicted that Cyclone Fani is likely to turn into a ‘severe cyclonic storm’ and may further develop into an ‘extremely severe cyclone storm’.



Tropical Cyclones

  • Cyclones developed in the regions between the Tropic of Cancer and Tropic of Capricorn, are called tropical cyclones.
  • The weather conditions of low latitudes, mainly rainfall regimes are largely controlled by tropical cyclones.
  • Tropical cyclones usually develop in summer season in the vicinity of Inter-Tropical Convergence Zone (ITCZ)over warm ocean surface.
  • Tropical cyclones are one of the mechanisms by which surface heat energy is redistributed from the equator to the poles.

Conditions necessary for development

  • Tropical cyclones are formed due to low pressure of thermal origin. The conditions favourable for the formation and intensification of tropical cyclone storms are:
    • Large sea surface with temperature higher than 27° C
    • Presence of the Coriolis force
    • Small differences in the vertical wind speed
    • A pre-existing weak- low-pressure area or low-level-cyclonic circulation
    • Upper divergence above the sea level system



Cyclones in India

  • India has a very long coastline which is exposed to tropical cyclones arising in the Bay of Bengal and Arabian Sea.
  • Indian Ocean is one of the six major cyclone-prone regions in the world.
  • In India cyclones occur usually in April-May (pre-monsoon), and also between October and December (post- monsoon).
  • The post-monsoon cyclones (in October and November), are usually stronger and more devastating.
  • The Eastern coastline is more prone to cyclones as about 80 percent of total cyclones generated in the region hit there.
  • The impact of the cyclones is mainly confined to the coastal districts, the maximum destruction being within 100 Km. from the centre of the cyclones and on either side of the storm track.
  • The maximum amount of damage caused by a cyclone happens during the time of the landfall.
  • The principal dangers from a cyclone include the gales and strong winds; torrential rain and high tidal waves (storm surges). Most casualties are caused by coastal inundation by tidal waves and storm surges.


Management of Cyclones:

  • There are many structural and non-structural measures for effective disaster management of cyclones.
    • Structural measures include construction of cyclone shelters, construction of cyclone resistant buildings, road links, culverts, bridges, canals, drains, saline embankments, surface water tanks, communication and power transmission networks etc.
    • Non-structural measures like early warning dissemination systems, management of coastal zones, awareness generation and disaster risk management and capacity building of all the stakeholders involved.


About India Meteorological Department (IMD)


  • The IMD is an agency of the Ministry of Earth Sciences of the Government of India.
  • Headquarter: Delhi and operates hundreds of observation stations across India and Antarctica.
  • Regional Offices: Mumbai, Kolkata, Nagpur and Pune.
  • Functions:
    • It is the principal agency responsible for meteorological observations, weather forecasting and seismology.
    • It has the responsibility for forecasting, naming and distribution of warnings for tropical cyclones in the Northern Indian Ocean region, including the Malacca Straits, the Bay of Bengal, the Arabian Sea and the Persian Gulf.
  • It is also one of the six Regional Specialised Meteorological Centres of the World Meteorological Organization.
  • In the past few years, the IMD’s capability to predict and track the trajectories of tropical cyclones has improved considerably, leading to timely warnings and effective response measures.
  • As a result, the damage caused by these cyclones has been significantly reduced.