As 25cm rain pounds city, life comes to a standstill. With hospitals inundated, patients and newborns rescued by boat, working hours of government paramedics extended, ambulance services operate in disaster management mode.
The city and northern districts of Tamil Nadu received at least 13.6cm of rainfall or more on five days since November 13, but for the 24 hours between 2am on Tuesday and 2am on Wednesday is likely to be a record for almost 40 years, with it touching 24.65cm till 10.30pm and spiralling upward at an average rate of 2cm an hour since Tuesday evening.
Starting on November 9, when the city received 13.6cm, through November 13 (14.9cm), November 23 (13.9) and November 16 (24.6cm), the city’s wettest month has never been wetter than it has this year, the Met office measuring the rain in the state till midnight on November 30 at 119.73cm, shattering the 1918 record of 108.8cm.
Though the northeast monsoon was tardy this year, later than normal by more than 10 days when it started on October 28, the heavy showers more than compensated for that. The city has so far received 127cm till 10.50am on Tuesday .
Such heavy rainfall is not to Chennai, say metrology experts. “Chennai has had heavy rainfall earlier too,” former deputy director general Y E A Raj said. “The maximum rainfall in a single day so far was in 1976 when the city got 45cm of rain in 24 hours. This a record still holds.”
“The city also received record rainfall for June this year due to a cyclone,” Raj said. “Extreme rainfall on a single day is something that the city has witnessed but this year it has been raining very heavily for a sustained period.”
Weather experts said rainclouds with a radius of 100km have surrounded Chennai. “Due to the rain-bearing clouds it has raining continuously since [Tuesday] morning,” Raj said. “It will continue for two more days before the intensity wanes.”
On November 23, the city received 10cm within 4 hours. Those showers flooded roads and entire neighbourhoods. “But Tuesday’s rain has been much more devastating because several parts of the city were already waterlogged,” an official said.
As in the previous days, a trough in the Bay of Bengal caused Tuesday’s downpour.
“Rainfall in the northern districts of the state, including Chennai, was due to two low pressure systems in the Bay of Bengal,” a Met department official said.”The rainfall on Tuesday is also due to a trough in the bay . Rainclouds have surrounded the city and it will continue to rain for at least two more days.”
The rain blacked out many localities in Chennai, with TNEB shutting down electricity supply to prevent electrocution (the cause of at least 15 deaths in the city this monsoon and a total of 40 across the state), and left almost every locality waterlogged.