The city of Chennai is located on the east coast of India, which is also known as the Coromandel Coast. Chennai is largely dependent on NE monsoon, since 65% of rains are received in this season. Cyclones and depressions are common features during the season. Cyclones in particular are really unpredictable. They can even move towards Orissa, west Bengal, Bangladesh, and also Myanmar. The season between October and December is referred as the NE monsoon period. Floods are common during this period. In 2015 Chennai received record breaking rains since 1918, which caused massive floods.
Cyclones
Cyclones are highly unpredictable. The entire east coast is vulnerable during the monsoon period. For example, In 2007 a major cyclone named "Cyclone Sidr" skipped Chennai and headed towards Bangladesh. The result was a failure of NE monsoon in Chennai, that particular year. Even in the past,there has been many occasions where Cyclones had a great influence in the monsoon.