Decoded: Wind speed to extent of damage, things to know about Cyclone Nivar

The severe Cyclone Nivar over the Bay of Bengal moved west-northwestwards on Wednesday morning at a speed of 11 km per hour, and lay centred over southwest Bay of Bengal about 240 km east-southeast of Cuddalore in Tamil Nadu — some 250 km east southeast of Puducherry and 300 km south-southeast of Chennai.  

Nivar, which has intensified into a “very severe cyclone”, is projected to cross Tamil Nadu and Puducherry coasts between Karaikal and Mamallapuram between the midnight of November 25 and the early hours of November 26 at a wind speed of 120-130 kmph gusting to 145 kmph.

So what are the key features of this cyclone and what could be its impact. The India Meteorological Department (IMD) has an assessment.

Cyclone name: Nivar

When is it expected to hit the mainland: IMD says the storm, which has now developed into a severe cyclone, is expected to hit Tamil Nadu and Puducherry coasts during the midnight of November 25 and the early hours of November 26.

Expected wind speed: Around 120-130 km per hour with gusting up to 145 km per hour.

Expected rainfall: Fairly widespread to widespread rainfall and thunderstorm very likely over coastal and north interior Tamil Nadu, Puducherry and Karaikal, south coastal Andhra Pradesh and Rayalaseema during November 25 and 26; and southeast Telangana during November 26.

Sea condition: Very high over Southwest Bay of Bengal and very rough to high along and off Tamil Nadu, Puducherry, south Andhra Pradesh coasts and over the Gulf of Mannar.

Tidal waves: Tidal wave of about 1-1.5 m high above the astronomical tide is very likely to inundate the low-lying areas of north coastal districts of Tamil Nadu and Puducherry near the place of cyclone landfall.

Damage expected: Over Nagapattinam, Mayiladuthurai, Cuddalore, Villupuram and Chengalpattu districts of Tamil Nadu, and Karaikal and Puducherry.

Kind of damage expected: IMD says damage could be in the form of total destruction of thatched houses or extensive damage to kutcha houses. Some damage to old pucca houses could also be expected. There is a potential threat from flying objects. That apart, power and communication poles could get bent, while major damage can happen to kutcha and pucca roads along with disruption of railways, overhead power lines and signalling systems. 

Any other place where damage could be expected:  IMD says damage could also be expected over Tiruvarur, Kanchipuram, Chennai and Tiruvallur districts of Tamil Nadu and adjoining Andhra Pradesh.

Action suggested: Total suspension of fishing operations. Mobilise evacuation from coastal areas. Coastal hutment dwellers to be moved to safer places. People in affected areas to remain in safe places and indoors. Judicious regulation of rail, road and air traffic. Movement in motor boats and small ships unsafe.

Chennai airport shuts operations: The Chennai airport on Wednesday evening said that it has suspended flight operations from 7 pm on Wednesday till 7 am on Thursday 

Railways cancels trains: The Railways has cancelled over a dozen special trains on November 25 and 26 scheduled to either originate from and terminate in the southern states, and offered full refund

Preparations: National Disaster Response Force has positioned 22 teams (12 in Tamil Nadu, three in Puducherry and seven in Andhra Pradesh) at the likely affected areas, while teams have been kept in reserve at Guntur (Andhra Pradesh), Thrissur (Kerala) and Mundli (Odisha) to meet additional requirements. All teams have reliable wireless and satellite communications, tree cutters or pole cutters for post-landfall restoration. State government has made over 200 camps to shift people from coasts to safer areas.