Chennai recorded the heaviest rainfall on record since 2015 after it received more than 200 mm (20 cm) of rainfall beginning November 6, 2021. Nungambakkam received (215 mm) 21.5 cm of rainfall, the highest recorded in 24 hours since the 2015 Chennai rains. The Indian Meteorological Department (IMD) has issued an orange alert for Chennai while predicting that very heavy to heavy rains mains may continue till November 9 morning.
Chennai Rains: Orange alert, Waterlogging, schools shut, 2,000 cusecs water released from reservoirs – Key Updates
•The IMD has predicted the formation of a cyclonic circulation over the Southeast Bay of Bengal and a low-pressure area around November 9, 2021.
•The IMD has also predicted squally winds gusting upto 60 kmph over Southeast Bay of Bengal during November 9-10 and off Tamil Nadu, Andhra Pradesh coast during November 10-11, 2021.
•A very heavy to heavy rainfall warning for November 10 has also been issued as a thunderstorm is likely to occur over Chennai, Puducherry, and Tamil Nadu.
•Fishermen are advised not to venture into the southeast Bay of Bengal and off Tamil Nadu coast during November 10-11, 2021.
•Chennai rains have led to the inundation of most areas and leading to waterlogging and shutting of schools and colleges in some areas.
•Following such heavy record rains, surplus water from reservoirs around Chennai including Chembarambakkam, Phuzal, and Poondi was released in a phased manner of upto 2,000 cusecs. Alert to the people in the low-lying areas was issued.
•PM Modi spoke to CM Stalin to discuss Chennai rains and offer relief assistance. Four NDRF (National Disaster Response Force) teams have been deployed in Madurai, Chengalpattu, and Thiruvallur.
Spoke to Tamil Nadu CM, Thiru @mkstalin and discussed the situation in the wake of heavy rainfall in parts of the state. Assured all possible support from the Centre in rescue and relief work. I pray for everyone’s well-being and safety.
— Narendra Modi (@narendramodi)
November 7, 2021
Tamil Nadu | 4 NDRF (National Disaster Response Force) teams have been deployed in Thiruvallur, Chengalpattu and Madurai as IMD issues alert of cyclonic circulation & heavy rains for next two days
— ANI (@ANI)
November 7, 2021
Chennai Rains: Highest rainfall recorded in Chennai since 2015
Chennai has been receiving very heavy to heavy rains since November 7, 2021, and is likely to continue experiencing heavy downpours aided by cyclonic circulation. Nungambakkam received 215 mm (21.5 cm) of rain, the highest volume of rainfall recorded in 24 hours since the 2015 Chennai rains. Heavy rains in Chennai have led to flooding in several areas. In 2015, Chennai had recorded 250 mm (25 cm) rainfall. In 1985, Chennai recorded between 250 mm to 330 mm (25 to 33 cm) rainfall across two different dates. The 1976 Chennai rains recorded the all-time high rainfall at 450 mm (45 cm) in 24 hours.
What caused heavy rains in Chennai, Tamil Nadu?
Chennai rains are mostly witnessed during the Northeast Monsoon between October to December. However, since the onset of the Northeast monsoon in October 2021, Puducherry and Tamil Nadu have received 43 per cent excess rainfall. Districts including Tirunelveli, Coimbatore, Villupuram, Tiruvarur, Karur, Erode, Pudukottai, Cuddalore, and Perambalur have received more than 60 per cent of normal rainfall during this monsoon season, said CM Stalin.
In 2021, the Northeast monsoon has been largely impacted by continued La Nina which is a complex weather pattern caused due to differences in ocean temperatures in the equatorial band of the Pacific Ocean. The 2015 Chennai rains were caused due to the El Nino impact on the Northeast monsoon. El Nino is a weather pattern that causes drastic atmospheric changes, leading to excess rainfall or cyclones.