Tamil Nadu and neighbouring areas are bracing for heavy rainfall with cyclone Mandous expected to cross India’s coast between Puducherry and Sriharikota on the night of December 9, the India Meteorological Department (IMD) said Thursday.
The well-marked low-pressure area over southeast Bay of Bengal intensified into a depression on December 6 and it further intensified into a “deep depression” and lay about 750 km off Chennai as of Wednesday.
In its bulletin issued on Thursday, the IMD said the cyclone “is expected to move west-northwest and cross north Tamil Nadu, Puducherry and adjoining South Andhra Pradesh coast between Puducherry and Sriharikota with a wind speed of 70 km per hour around midnight of December 9.”
As per the bulletin, heavy to very rainfall is likely to occur at isolated places in Cuddalore, Mayiladuthurai, Nagapattinam, Tiruvarur, Thanjavur and Pudukkotai on Thursday. Heavy rainfall is likely to occur over Kancheepuram, Chengalpattu, Villupuram, Kallakurichi, Perambalur, Ariyalur, Tiruchirapalli, Sivaganga and Ramanathapuram.
On Friday, extremely heavy rainfall is likely to occur at one or two places over Kancheepuram, Chengalpattu and Villupuram districts. Heavy to very heavy rainfall is expected in Chennai, Tiruvallur, Ranipet, Vellore, Tirupattur, Tiruvannamalai, Kallkurichi and Cuddalore. Heavy rain is likely to occur at isolated places in Dharmapuri, Salem, Namakkal, Karur, Tiruchirapalli, Perambalur, Ariyalur, Mayiladuthurai, Nagapattinam, Tiruvarur, Thanjavur, Pudukkotai, Sivaganga, Madurai and Dindigul.
On Saturday, heavy to very heavy rain is likely to occur at isolated places in Krishnagiri, Dharmapuri, Tirupattur, Vellore, Ranipet, Tiruvannamalai, Chengalpattu, Kancheepuram, Chennai and Tiruvallur districts. Heavy rain is likely to occur at isolated places in the Nilgiris, Erode, Salem, Kallakurichi and Villupuram districts.
A cyclone is a low pressure system that forms over warm waters. Essentially, it is a system of high speed winds rotating around a low-pressure area, with the winds blowing counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
According to the World Meteorological Organization, “Tropical cyclones are one of the biggest threats to life and property even in the formative stages of their development. They include a number of different hazards that can individually cause significant impacts on life and property, such as storm surge, flooding, extreme winds, tornadoes and lighting. Combined, these hazards interact with one another and substantially increase the potential for loss of life and material damage.”
Cyclones that form in every ocean basin across the world are named by the regional specialised meteorological centres (RSMCs) and Tropical Cyclone Warning Centres (TCWCs). There are six RSMCs in the world, including the India Meteorological Department (IMD), and five TCWCs.
As an RSMC, the IMD names the cyclones developing over the north Indian Ocean, including the Bay of Bengal and Arabian Sea, after following a standard procedure. The IMD is also mandated to issue advisories to 12 other countries in the region on the development of cyclones and storms.
The months of October-November and May-June see storms of severe intensity develop in the North Indian Ocean — comprising the Bay of Bengal and the Arabian Sea — with an average of five developing in a calendar year. According to the IMD, of these five storms, four are in the Bay of Bengal and one in Arabian Sea.