CHENNAI: At a time when Chennaites are yet to completely recover from flooding caused due to recent incessant rains, another rain-filled weather system is heading towards north Tamil Nadu and could dump heavy to very heavy rains over Chennai and neighboring districts between November 17-19.
The regional meteorological centre here initially issued an Orange Alert, meaning rains ranging from 12 cm to 20 cm, for Tiruvallur, Chennai, Kancheepuram, Chengalpattu, Ranipet, Vellore, Villupuram, Tiruvannamalai, Kallakurichi, Cuddalore, Mayiladuthurai and delta districts. On November 19, a red alert has been been issued for Chennai, Tiruvallur, Kancheepuram and Ranipet districts
In the mid-day forecast bulletin on Monday, the Indian Meteorological Department said a low-pressure area lies over the north Andaman Sea and neighborhood. It is likely to move west-northwestwards and become well marked over east-central and adjoining southeast Bay of Bengal during the next 48 hours. Thereafter, it is likely to continue to move nearly westwards and reach west-central and adjoining southwest Bay of Bengal off south Andhra Pradesh-north Tamil Nadu coasts on November 18.
All the weather models are showing massive rains north of Chennai starting November 17 evening.
Initially, the models suggested the system would intensify into a cyclone and head towards Visakhapatnam and Odisha coast, but now it will only be a well-marked low pressure coming towards north Tamil Nadu and south Andhra Pradesh. "If it weakens further, Chennai would get bulk of the rains," said K Srikanth, independent weather blogger who runs the popular ChennaiRains Twitter handle.
Drone survey
To assess the vulnerable areas, N Subbaiyan, director of Tamil Nadu State Disaster Management Authority, told The New Indian Express a drone survey was carried out to identify lakes and other water bodies that can breach and cause flash floods.
"We are mobilizing and keeping ground teams on standby to meet any eventuality based on sound planning. The past few bright and sunny days provided much-needed breathing space. We have received the alert and all the precautionary measures are taken," a top official said.
Another important lesson that was learned from past disasters was to regulate the flood water discharge from reservoirs in such a way that water drains smoothly causing minimal trouble to people living downstream.
"We are maintaining around 75 percent storage in most of the reservoirs and once the meteorological department confirms the location and intensity of rains, we will adjust the outflows accordingly," he added.