Intermittent rain lashed many places in and around Chennai on November 18 as the depression over the southwest Bay of Bengal moved closer inland. The India Meteorological Department said the depression lay 100 km south-southeast of Chennai at around 9 p.m. IST, and moved at a speed of 18 kmph over the past few hours.
The IMD withdrew the red alert for Chennai and surrounding districts as there were slim chances of extremely heavy rain. However, an orange alert, indicating heavy to very heavy rain, has been issued for Chennai and neighbouring districts as the system may cross between Puducherry and Chennai in the early hours of November 19.
S. Balachandran, Deputy Director-General of Meteorology, Chennai, said the land interaction had sheared the depression and reduced cloud cover. The upper portion of the weather system had already entered the land.
The system would trigger heavy to very heavy rain in several interior districts, including Tiruvannamalai, Salem and Krishnagiri, on November 19. Places, including Chennai and Kallakurichi, may experience heavy rain on November 19. On November 18, several places received moderate to heavy rain. As the system moved closer to the Tamil Nadu coast, places such as Cuddalore (10 cm), Puducherry (15 cm), Thirukovilur in Kallakurichi (11 cm) and Cheyyur in Chengalpattu district (8 cm) received heavy rain till 5.30 p.m. Meenambakkam in Chennai recorded 5 cm, Nungambakkam, 3 cm, and West Tambaram, Villivakkam, Anna University and MRC Nagar in Chennai and Tiruttani, 4 cm each.
Several weather stations received considerable rain during the past 24 hours ending 8.30 a.m. on November 18. Kundadam in Tiruppur district registered 20 cm, the day’s heaviest rainfall in the State.
A holiday has been declared for schools and colleges in several districts, including Chennai, Vellore, Tirupattur, Ranipet and Perambalur.
In Chennai, intermittent rain since the early hours of November 18 increased waterlogging in parts such as Pulianthope and T. Nagar that are yet to recover from the torrential rain last week. Power supply to many areas was disrupted following the heavy rain forecast. Five cattle head were electrocuted when they came into contact with a live wire at Medavakkam.
Mr. Balachandran said the rain in Chennai might decrease from November 19 noon. However, the wet weather in the State might continue till November 22. The intensity of rain in the Chennai region might reduce because of the land interaction with the weather system.
Meanwhile, the Central Water Commission has warned of an increase in the level in the rivers around the city, and in districts such as Cuddalore, Villupuram and Tiruvannamalai. This may lead to inundation of surrounding areas till November 20. The Sathanur and Veedur dams may get significant flows.
The Water Resources Department increased discharge from the Chembarambakkam, Red Hills and Poondi reservoirs as more inflows from the catchments were expected. According to the Tiruvallur district administration, the discharge from the Poondi reservoir was stepped up to 12,000 cubic feet per second (cusecs) as more floodwater was expected to flow from the Nagari, Nandhi and Kosasthalaiyar rivers.