Brief note on Forecasting and warning Systems of Cyclone in India

Cyclone forecasts are provided through six-cyclone warning centers located at Kolkata, Bhubaneswar, Visakhapatnam, Chennai, Mumbai and Ahmedabad. These centers have their distinct area wise responsibilities covering both the east and west coasts of India and the oceanic areas of the Bay of Bengal and the Arabian Sea, including Andaman & Nicobar and Lakshadweep.

Cyclone warnings are issued to the All India Radio (AIR) and the Doordarshan for broadcast/telecast in different languages. Cyclone warnings are also given to control room and Crisis Management Group in the Ministry of Agriculture, Government of India, who are finally responsible for coordinating various activities of Centre and State Governments and other agencies in respect of cyclone warnings. Forecasts and warnings are simultaneously communicated to the States and the Districts likely to be attached. Ports, airports and other user agencies also receive the forecasts and warnings at the same time.

Cyclones are tracked with the help of INS AT, powerful cyclone detection radars and conventional meteorological observations including weather reports from ships. At present cyclone detection radars are installed at (i) Kolkata, (ii) Paradeep, (iii) Visakhapatnam, (iv) Machilipatnam, (v) Chennai, (vi) Karaikal on the east coast; and (vii) Goa, (viii) Cochin, (ix) Mumbai and (x) Bhuj along the west coast. Present cyclone surveillance system in India is such that no cyclone in the region will go undetected at any time of its life cycle.

The important components of cyclone warnings are the forecast of future path and intensity of a eye tone and the associated hazardous weather. For the preparation of future position (path) of tropical cyclones and for estimation of storm surges, modern, and computer based techniques are used in addition to conventional methods. Intensity forecasts are made by using satellite techniques.

Cyclone warnings are provided in four stages. In its first stage, “Pre-Cyclone Watch” is maintained regularly during the cyclone seams and is intended to provide an early warning if conditions mature for a cyclonic disturbance to take birth on the seas. In the second state, a “Cyclone Alert” is issued 48 hours before the anticipated time of commencement of adverse weather along the coast. In the 3^rd stage, a “Cyclone Warning” is issued 24 hours before the cyclone’s anticipated landfall and is updated frequently. Warnings for the ports and fisheries start much earlier. Ports are warned day and night through a specially designed port warning system. Informatory messages on cyclones are issued to All India Radio and Doordarshan much earlier, as soon as a tropical cyclone is detected in the Bay of Bengal or in the Arabian Sea.

Lastly, the 4^th stage of warning comprises the “post-landfall scenario” which commences about 12 hours before anticipated landfall and continues so long as cyclone-force winds (60 kmph or more) are effected in the affected areas overland.

Cyclone warnings are disseminated through the following means:

i. Telegrams with highest priority,

ii. Telecast through Doordarshan,

iii. Broadcast through AIR,

iv. Bulletins to the press,

v. Broadcast through Department of Telecommunications, Coastal Radio Stations for ships in the high seas and coastal areas,

vi. INSAT based Disaster Warning System, and

vii. Point to point direct channels to the Central and State Government functionaries and other user agencies.

In addition to above, cyclone warnings are disseminated through tele-printers, telex, facsimile arid telephones wherever such facilities exist with the recipients.

The warning bulletins are issued normally at hourly intervals, but more frequently when needed. Likely areas threatened by cyclone, heavy rainfall, magnitude of destructive winds and probable inundation of coastal areas by storm surges are some of the elements included in the bulletins. On receipt of warnings, the Government officials and other authorities take appropriate measures to safeguard’ lives if’ necessary by evacuating people from vulnerable areas to safer places.

Landline telegram, telex and telephones are often among the first casualty during a cyclone situation because the overhead lines and underground cables are affected by strong winds and heavy rain during cyclone. To overcome this difficulty, a satellite based dependable and unique communication system known as Disaster Warning System (DWS) has been developed in India. Through this system, rapid and direct dissemination of cyclone warnings in local languages is made via INSAT satellite to designated addresses in the vulnerable areas. At present, Disaster Warning System is working along coastal areas where about 250 DWS sets have been installed in places such as blocks, taluq offices and police stations. Disaster warning sets are also located in the H. Q. of Coastal States and Districts. The system has been successfully utilized in cyclone situations and found to be very useful. About 100 more DWS sets are to be installed in the coastal areas.