With nearly two months to go for 2021 to come to a close, this metropolis has already achieved its annual average rainfall of 140 cm, thanks to consistent showers since the beginning of the year and the incessant rains since November 6 that have brought the city to a standstill.
The city has also achieved the monthly average for November during the North-east Monsoon (NEM) in the first eight days of the month. While the average rainfall for November is 37.4 cm, the rainfall received from November 1 to 8 is 41.5 cm, data available with the IMD said.
The city received 21 cm of rainfall in just 24 hours from November 6 to November 7 though there was no “specific warning” about heavy to very heavy rains. The non-functioning of two radars was cited as the reason for the MeT department not predicting heavy to very heavy rainfall in the city.
“Dryline thunderstorms” and “weak systems” in the Bay of Bengal are some of the reasons why the city continues to receive heavy rainfall since October-end without any break.
“The weak systems favour us and that is why we have been getting heavy rains since October 29 without any break. The non-stop rains are because of the favourable weather conditions. We will continue to get good rains for the next couple of days,” Pradeep John, an independent weather blogger, said.
John also added that the low pressure which is likely to be formed between November 10 and 12 will bring heavy to very heavy rainfall even if it does not strengthen itself to become a high-wind cyclone.
According to the data available, the IMD observatory in Nungambakkam in Chennai reached its annual average of 140 cm on Monday, while the observatory in Meenambakkam has recorded 133 cm against the annual average of 138 cm.
Also Read | IMD warns of extremely heavy rain in parts of Tamil Nadu, Andhra Pradesh on November 10, 11
K Srikanth, another weather blogger, told DH that 2021 has been a “good year” in terms of rainfall for the city. “Except for a month or two, 2021 has been a very good year for Chennai regarding rains. Consistent rains throughout the year have helped the city in more ways than one. Though we have another four weeks to fully realise the NEM, the city has already crossed the annual average rainfall,” he said.
The city did not experience any drought or water shortage in 2021 partly due to lessons learnt in 2019 when the water crisis hit Chennai and the continued rains since January. The reservoirs that supply drinking water to Chennai are brimming even as excess water is being released.
When asked about the 21 cm rainfall in just 24 hours, the highest since 2015, Srikanth said occasionally the city gets thunderstorms due to dryline thunderstorms. “When the winds from the land that is dry and winds from the sea that are moist converge, it triggers intense thunderstorm. That is the reason the city experienced continuous thunderstorms,” he added.
The weather bloggers said the city’s water storage mechanism may have also reached the saturation level due to rainfall throughout the year.
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