Normally, northeast monsoon brings heavy rain in the southern coastal region in Tamil Nadu, during November and December every year. But, in the year 2015, Tamil Nadu state was badly affected by torrential rain. The extremely heavy spells of rain is due to the El-Nino effect.
In 2015, the temperature of East pacific ocean got warm up highly and the Indian ocean & Bay of Bengal have cold temperature. Cyclone is caused when the Sea Surface Temperature(SST) is warm. Normally cyclones forming in Central Bay of Bengal due to warm weather, will move in northwest direction towards Andra Pradesh & Orissa coast. But, this year Central bay of Bengal remained cool.
But, weather in South Bay of Bengal became warm causing heavy rain in Tamil Nadu coastal regions. The concept of storm-water drains was abandoned in Chennai due to development activities. So, the city has got no space for the water to flow out. We should learn a lesson to do the right thing to protect us from natural calamities.