CHENNAI: The southern districts of Tamil Nadu which faced an extremely heavy rainfall for the past three days could heave a sigh of relief as IMD officials have said that the rain intensity may reduce from Tuesday. Bloggers termed the rainfall a once in a lifetime phenomenon.
There are also chances of light to moderate-intensity rainfall in Chennai city and suburbs for the next two days.
As of Monday 8.30am, 39 places received extremely heavy rainfall of 21cm and more. Kayalpattinam in Tuticorin received 95cm, and Tiruchendur recorded 69cm. The intensity of the rain has started to reduce. By 7.30pm, Tiruchendur recorded 28mm,
Virudhunagar
14mm.
S Balachandran
, deputy director general of IMD, said it was the first time a cyclonic circulation brought such massive amounts of rainfall. The circulation was also slow, which led to the downpour.
Dodging a question from the media on why IMD did not forecast the quantum of rainfall, which weather bloggers were able to do, Balachandran said the national weather agency had upgraded the alert to red on Sunday morning after chances of rain increased. He explained there are only three types of rain warnings: yellow alert issued for a forecast of 7cm to 11 cm of rainfall in 24 hours, orange alert issued for 12cm-20cm of rain, and red alert for 21cm and above. He also said the rainfall was not a cloudburst as it sustained through the day and was widespread.
"We had issued a heavy to very heavy rainfall forecast (orange alert) for Sunday. It was upgraded to red alert (extremely heavy rainfall) on Sunday morning after the chances of such rainfall increased. There is no alert beyond a red alert. For 95cm or 65cm, we cannot issue a separate alert," he said. "Based on scientific assessment, this much rainfall is not expected from a cyclonic circulation. With climate change, we can expect such types of events in the coming years," he added.
For Tuesday, the agency has forecast heavy rainfall at one or two places over Kanyakumari, Tirunelveli, Tuticorin, and
Tenkasi
districts.
Chennai and its suburbs are likely to receive light to moderate rainfall in some areas. The skies may be partly cloudy. Temperatures may be a maximum of 30°C-31°C and a minimum of 24°C-25 °C.
The historic rainfall has pushed rain records in Kanyakumari to 1050.7mm, 103% above normal, registered since October 1. Tirunelveli recorded 1123.8mm, 135% above normal; Tuticorin recorded 701.4mm, 68% above normal; and Tenkasi recorded 799.2mm, 80% above normal.
The official said research studies show that in the coming years, northeast monsoon rainfall may be above normal over south Tamil Nadu, and chances of precipitation extremes or heavy rainfall will increase.
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