TN witnessed more extreme weather patterns past 2 decades

Tamil Nadu witnessed a change in weather conditions the past two decades with extreme rainfall and droughts getting more frequent, according to weather experts. However, they clarify that it is natural and that the State is dependent on seasonal rainfall by at least 50 per cent.

The years 2005 and 2021 recorded the highest amount of rainfall annually against the normal. “The change in weather condition is natural, and it cannot be predicted for the long term. In the past two decades (2000 - 2021), both Tamil Nadu and Chennai witnessed excess rainfall and droughts.

The year 2005 saw extreme rainfall with over 53 per cent against the normal, while the following year it was minus 6 per cent. The State recorded the highest amount of annual rainfall in 2021 with 1,379 mm compared to 2015 which was 1,214 mm,” said Dr S Balachandran, deputy director-general of Meteorology, Regional Meteorological Centre (RMC), Chennai.

From 2000 to 2021, in Tamil Nadu, normal rainfall was recorded for 10 years during the Northeast Monsoon and 13 years when the annual rainfall is taken into consideration. For six years, the State received excess rainfall and only during one year it witnessed large excess rains during the monsoon.

Similarly, as far as Chennai is concerned, 12 years during the 20-year-period the city recorded normal rains annually, but only six normal years during the monsoon.

Excess rainfall was received for five years both annually and seasonal, and three years with large excess rainfall during northeast monsoon while one year had a large excess of annual rainfall.

“There is no specific reason for weather change conditions for Tamil Nadu. In 2021, the State witnessed more low-pressure systems, where the Bay of Bengal was active during the northeast monsoon, bringing in intense rainfall. However, there was not much rainfall in 2019, as at least four to five cyclones formed in the Arabian Sea, and we received easterly wind so interior districts of Tamil Nadu witnessed good amounts of rainfall,” said Tamil Nadu weatherman Pradeep John.

He added that the State also recorded drought in 2003, 2016, and 2017, where it received very moderate rainfall. From 2004-to 2011, the State received consistent rainfall, because it is not normal to receive rainfall continuously for seven years. But for the next three years, there was moderate rain but did not have enough rain for the inflow. In 2016, the monsoon failed, as 50 per cent of rainfall is dependent on seasonal rainfall, however, Chennai is dependent on 70 per cent of rainfall during the northeast monsoon alone.