Torrential rains lash Tamil Nadu as Northeast monsoon intensifies

With overnight rains bringing heavy inflows, the floodgates of two major reservoirs of Chennai at Chembarambakkam and Poondi were opened wider to regulate the water level and prevent flood risk on Wednesday (October 22, 2025).

The well-marked low pressure area that lies over southwest Bay of Bengal off the Tamil Nadu coast brought torrential rains in several parts of Tamil Nadu. The 90 major water bodies in the State now have a storage of 87.7% of their total capacity of 224.34 thousand million cubic feet.

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Likelihood of depression

As it continues to move northwestwards, the Regional Meteorological Centre (RMC), Chennai has predicted a possibility of the system gathering strength as a depression over the southwest and adjoining westcentral Bay of Bengal off north Tamil Nadu and south Andhra Pradesh coasts by Wednesday evening.

It is likely to move across north Tamil Nadu, Puducherry and south Andhra Pradesh coasts during the next 12 hours.

Water bodies

Chembarambakkam reservoir, Chennai’s key drinking water source spread over 25.51 sq.km., received an inflow of 2,170 cubic feet per second (cusecs) of water. This also includes water diverted from Poondi reservoir through link canal.

Officials of the Water Resources Department said the water bodies upstream feeding the reservoir are fast filling up. The water level at Chembarambakkam reservoir stands at 20.84 feet on Wednesday (October 22) compared to 18.52 feet on October 18.

With storage rising to 2,815 millon cubic feet (mcft) against 3,645 ft, the department has increased water discharge from 100 cusecs to 500 cusecs into Adyar river on Wednesday morning. The measure would enable balance storage and accommodate heavy inflows. The department has issued flood warning to areas downstream and along Adyar river

Similarly, the water release from Poondi reservoir has been stepped up to 4,500 cusecs to maintain its water level at 33.05 feet, two feet lower than full level.

Rainfall received

Northeast monsoon in its vigorous mode pounded several districts across the State. Periyakalapet in Puducherry recorded extremely heavy rainfall of 25 cm in the 24 hours ending 8.30 a.m. Various weather stations and rain gauges in and around Puducherry, Villupuram and Cuddalore received very heavy rainfall.

Widespread, intense rainfall lashed many other districts like Chennai, Kallakurichi, Tiruchi, Karur and Chengalpattu too.

Forecast

In its nowcast, the RMC has predicted light to moderate rainfall to cover north districts of Tamil Nadu including Chennai, Ranipet and Cuddalore and also Kanniyakumari district apart from Puducherry till 1 p.m.

The RMC has updated forecast and restricted red alert to Ranipet and Tiruvallur districts till 8.30 a.m. on Thursday (October 23). Many other north Tamil Nadu districts including Chennai have been sounded orange alert for the same period.