CHENNAI: As many as 29 weather stations in Tamil Nadu recorded extremely heavy rainfall in 24 hours from 8.30 am on December 12, with the highest being Oothu in Tirunelveli which received 540 mm (54 cm).
Such was the rains in Tirunelveli that seven out of ten stations that recorded such heavy rainfall are in the district.
The second highest was Ambasamudram, also in Tirunelveli, which recorded 366 mm rainfall between 8.30 am on December 12 and 8.30 am on December 13.
Kovilpatti in Thoothukudi recorded 364.7 mm, Kannadian Anicut in Tirunelveli 351.4 mm, and Kakkachi in Tirunelveli 350 mm were among the top-five areas that received the heaviest rainfall.
Among the rest of the stations that reported extremely heavy rainfall (204.5 mm or more) are: Manjolai, Tirunelveli (320 mm); Ayikudi, Tenkasi (312 mm); Nalumukku, Tirunelveli (310 mm); Lalpet, Cuddalore (309.7 mm); Manimutharu, Tirunelveli (298 mm); Palayamkottai, Tirunelveli (261 mm); Manalmedu ARG, Mayiladuthurai (256.5 mm); Srimushnam, Cuddalore (241.2 mm); Shenkottah, Tenkasi (240 mm); Ramanadhi Dam Section, Tenkasi (238 mm); KM Koil, Cuddalore (237.4 mm); Servalar Dam, Tirunelveli (237 mm); Tenkasi (230 mm); Cheranmahadevi, Tirunelveli (225.2 mm); Mayiladuthurai (223.5 mm); Papanasam, Tirunelveli (221 mm); Kilacheruvai, Cuddalore (219 mm); Avadi, Tiruvallur (215 mm); Pelandurai, Cuddalore (213.2 mm); Sethiathope, Cuddalore (212.3 mm); Gundar Dam, Tenkasi (208 mm); Tiruvidaimaruthur, Thanjavur (206.8 mm), Tirunelveli AWS, Tirunelveli (206 mm); and Jayamkondam, Ariyalur (205 mm).
The India Meteorological Department (IMD) defines rainfall categories as:
-- Heavy rain: 64.5–115.5 mm
-- Very heavy rain: 115.6–204.4 mm
-- Extremely heavy rain: 204.5 mm or more.