Night-long showers in Chennai raise concerns about wet season ahead

The city’s wettest day of the year so far also led to waterlogging in several areas, exposing its unpreparedness to face the northeast monsoon next month.

Slowing traffic during the early part of the day to a crawl, waterlogging took residents by surprise on Thursday morning. However, with the rain letting up by 8.30 a.m. in most areas, water drained by afternoon.

No doubt, the rain was heavy — thundershowers lashed the city from late on Wednesday, and the weather station at Nungambakkam recorded 10.4 cm of rainfall for a 24-hour period, ending 8.30 a.m. on Thursday. Meenambakkam too received 9 cm in the same period. Rain gauges in Ennore and Madhavaram recorded rainfall of about 11 cm and 10 cm respectively.

Meteorological Department officials said the all-night showers made it the wettest day of the year, with the highest rain for a single day in September, in a decade. The city had earlier recorded nearly 9 cm of rainfall on September 11, 2013.

The rain also brought back concerns among residents about the government’s preparedness ahead of the northeast monsoon that will set in later next month. Despite the Corporation spending the most on stormwater drains during the past two regimes, city roads witnessed heavy waterlogging in several areas.

In the north, Vyasarpadi, Mannady and Pulianthope came under sheets of water. Motorists faced difficulty, after their vehicles stopped on the roads. Inundation was reported in many streets in Kilpauk, Anna Nagar, Vepery, Kodambakkam, Pallavaram, T. Nagar and other localities.

Waterlogging could be seen in front of many schools from Kilpauk to T. Nagar. Schoolchildren had a tough time, as showers continued till the time the schools opened. The Gengu Reddy subway in Egmore, which was flooded, was closed for traffic, and vehicles were not allowed to pass through. Several areas in the western suburbs of Ambattur and Avadi were also inundated, affecting normal life early in the morning.

Commuting was difficult till about 9 a.m. The movement of vehicles was hampered due to waterlogging at many places including at Koyambedu, Kilpauk, Choolaimedu, Kodambakkam, T. Nagar, Anna Salai and Anna Nagar.

Inflow into reservoirs

In what could be compared to a rainy day during the northeast monsoon, many places in Tiruvallur district also recorded heavy rainfall. Tiruvallur recorded a high of 22 cm of rainfall during the past 24 hours, followed by Poondi (21 cm) and Tamaraipakkam (15 cm).

The city reservoirs — Poondi, Cholavaram (14 cm) and Red Hills (10 cm) — too recorded heavy downpour. Inflow into the Poondi reservoir was 3,000 cusecs, following downpour in the catchment areas. Both Cholavaram and Red Hills lakes received an inflow of 400 cusecs. “The waterbodies have started receiving inflows, and we need more rainy days for improvement in storage,” said an official of the Water Resources Department.

S. Balachandran, Deputy Director General of Meteorology, Chennai, said an east-west shear zone, embedded with a cyclonic circulation over south Andhra Pradesh and north Tamil Nadu coast, influenced heavy thundershowers in Chennai and its neighbouring districts. Several weather interactions, including westerly trough, led to the widespread rainfall.

Mr. Balachandran said weather models indicated that rainfall activity may continue over the State for two or three days, due to the influence of the system. However, density of the thundershowers may vary in different locations. There is a chance of heavy rain in some places of north Tamil Nadu and the southern districts till Friday. Some districts that are likely to record heavy showers till Friday morning include Pudukottai, Tiruchi, Cuddalore, Madurai and Perambalur.