Five weather systems in the Bay of Bengal had paths similar to the recent Cyclone Michaung since 1971, bringing with it heavy rainfall over Chennai.
November 1976 and June 1996 were among those years when Chennai received similar downpour. Y.E.A. Raj, former deputy director general of meteorology, Chennai, said the depression in 1976 scraped both Tamil Nadu and Andhra Pradesh coasts and then recurved. The depression dumped nearly 45.2 cm of rainfall in Nungambakkam and 35 cm of rains in Meenambakkam. It is still an all-time record high rainfall in November.
Similarly, a cyclonic storm in June 1996 had brought a heavy rain spell of 11 cm on June 13 and 35 cm on June 14. The storm had passed close to Chennai, dumped rains and moved to A.P. The other weather systems in October 1982, November 1984 and October 2005 too brought downpour with similar tracks travelling close to the T.N. coast. In October 2005, heavy rains lashed the city between October 23 and October 28.
“We cannot describe the recent rain spell as unprecedented as we have had heavy rainfall episodes in the past too. There was flooding in Chennai during years like 1985 and 1997. Boats were involved in rescuing residents during one or two years and Adyar river was flooded,” he said.
Breaching benchmark
The 200 cm benchmark of Chennai’s annual rainfall has been frequently breached in the past three decades. There have been seven such years when the annual rainfall exceeded 200 cm in the city. Chennai’s average annual rainfall has increased in recent years.
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According to Meteorological department, Nungambakkam has recorded 210 cm of rainfall so far this year against its normal of 140 cm. Similarly, Meenambakkam has registered 217 cm of rainfall against the yearly share of 138 cm.
Weather blogger R. Pradeep John said 2005 tops the list with 256.6 cm of rainfall. Chennai had received more rainfall than now in 1943 and 1946 as well.
The intensity of rainfall has increased considerably in the recent years. In the past eight years alone, the city has received over 200 cm of annual rains in three years, he said.
Heavy rains in areas like Avadi and Poonamallee had brought heavy flow in Cooum river and areas downstream faced the impact earlier this week. Areas in upstream part of Adyar river received more rains in 2015, bringing in more inflow. This year, severe rains were concentrated in city areas compared to upstream localities of the river, he noted.
Published - December 09, 2023 01:54 am IST
