- The Indian subcontinent is one of the worst affected regions in the world. The subcontinent with a long coastline of 8,041 kilometers is exposed to nearly 10% of the world’s tropical cyclones.
- Majority of cyclones in India have their genesis over the Bay of Bengal and usually strike the east coast of India. On an average, five to six tropical cyclones form every year, of which two or three could be destructive.
- More cyclones occur in the Bay of Bengal than the Arabian Sea and the ratio is approximately 4:1. An analysis of the frequency of cyclones on the east and west coasts of India between 1891 and 1990 shows that nearly 262 cyclones occurred on the east coast and 33 cyclones occurred on the west coast during this period.
- The cyclones with severe intensity peak in October or November (e.g. Cyclone Phailin) and the ones of less intensity peak in May (e.g. Cyclone Mahasen).
- A fully matured cyclone develops a calm center or EYE with a ring of hurricane winds around it. But many cyclones do not develop to this stage. The 'Eye' if developed, has a diameter of 10 to 50 km and is free of any rain. Sometimes a double eye wall structure can also be seen when the storm becomes very intense.
- The disaster potential from a cyclone is particularly high at the time of landfall, due to the accompanying destructive wind, storm surges and torrential rainfall, increasing the phenomena of floods into inland areas and coastal territories.
- Nearer the eye of the cyclone, winds may hit a speed of 320 kmh.
- Cyclones vary in diameter from 150 to 1000 kilometers but their effects dominate thousands of square kilometers of ocean surface.
- The types of disturbances that form in the sea, according to their severity order, are:
Low Pressure
Depression
Deep Depression
Cyclonic Storm
Severe Cyclonic Storm
Very Severe Cyclonic Storm
And, Super Cyclone
- Cyclones are classified into five different levels on the basis of wind speed. These are from Category – 1 to Category – 5. The wind speed varies according to the category of the cyclone, from 90 kilometers an hour to 250 kmph and above.
- A tropical cyclone begins to weaken as soon as its source of warm moist air begins to ebb, or is abruptly cut off. This happens after the landfall. The weakening of a cyclone does not mean the danger to life and property is over.
- Andhra Pradesh, lying in the east coast of peninsular India, is the worst hit by cyclones every year.
- Although cyclones do not reach till central India, but in case of very severe cyclones, widespread rain is witnessed. Very severe cyclone, Phailin, brought widespread rain up to Chhattisgarh, Jharkhand and Bihar.
- 2013 is the first year, which has seen the formation of series of cyclones in India in quick succession. Phailin being the first cyclone and the most destructive so far. Phailin was followed by Helen and now, Lehar. Forecasts at Skymet show, there could be more cyclones on their way.
Photo by Samuel Marie-Fanon for EU/ECHO