North Chennai records up to 36 cm of rain overnight in the northeast monsoon's first intense spell

Parts of north Chennai received more than 30 cm of rain in a single night as the northeast monsoon brought its first intense spell to Tamil Nadu, PTI reported on Sunday, October 18. Parry's Corner recorded 36 cm and Kathivakkam 34 cm in the 24 hours ending 8:30 am Sunday, the highest figures in the Regional Meteorological Centre's bulletin, according to the PTI report published by Telangana Today and an account in DT Next. The weather department issued a red alert for Chennai for the 24 hours from Sunday afternoon, later lowering it to yellow.

How much rain fell

ETV Bharat reported that the heavy rain began at about 6:30 pm on Saturday, October 17, and continued until about 1:30 am. It gave slightly different station figures from PTI, citing Greater Chennai Corporation Commissioner Samiran:

• Parry's Corner (Parimunai): 35.4 cm
• Kathivakkam: 33.4 cm
• Sadankadu: 25.3 cm
• Thiruvottiyur: 21.8 cm
• Ennore: 20.8 cm

Six areas received more than 20 cm and 12 more than 11.5 cm, ETV Bharat said. DT Next reported on Monday that north Chennai had recorded 6 to 10 cm in under an hour on Saturday night. Weather expert Pradeep John told ETV Bharat the rainfall was comparable to the single-day deluge during Cyclone Michaung in December 2023. The meteorological centre called the event a localised cloudburst, while noting that a formal classification required more data, according to ETV Bharat.

Cause

The northeast monsoon set in over Tamil Nadu on October 15, according to an IANS report published by SocialNews.XYZ. DT Next attributed the downpour to the monsoon entering an active phase and to an upper-air cyclonic circulation over the southwest Bay of Bengal and the adjoining north Tamil Nadu coast, with a trough extending to the northwest Bay of Bengal.

Impact and response

The Greater Chennai Corporation said all 22 of the city's subways had been cleared of water and reopened by 6 am on Sunday, and that there were no casualties or major accidents, PTI reported. One National Disaster Response Force team and four Tamil Nadu Disaster Response Force teams were sent to vulnerable areas, nine relief centres were opened, and food was handed out in low-lying neighbourhoods.

Chief Minister C Joseph Vijay and Public Works Minister Aadhav Arjuna visited the corporation's Ripon Building headquarters, according to PTI. ETV Bharat quoted Arjuna as saying the Chief Minister was receiving hourly updates, and said IAS officers had been assigned to supervise work in all 15 zones of the city.

At Chennai airport, more than 20 flights were affected, ETV Bharat reported. Over 10 domestic arrivals circled for extended periods, and departures to cities including Singapore, Kuala Lumpur, Frankfurt, Abu Dhabi, Madurai, Mumbai and Delhi were delayed by one to two hours.

School Education Minister Rajmohan said on Sunday the government would decide on school holidays based on information from the meteorological centre and private weather observers. "We will decide at the appropriate time whether to declare holidays for schools," he said, according to IANS.

The forecast

DT Next, citing the Regional Meteorological Centre, listed orange alerts for heavy to very heavy rain in Theni, Tirunelveli and Madurai on October 20, and in the Nilgiris, Coimbatore, Madurai, Theni, Kanniyakumari, Tirunelveli and Dindigul on October 21. Chennai is under a yellow alert on both days. IANS reported that the department had forecast heavy rain in 26 districts.