The skies over Calcutta opened up late on Monday afternoon, bringing more than 100mm of rain in just an hour and inundating several roads. Rush-hour traffic was reduced to a crawl as cars with headlights on honked their way through early dusk and lashing rain, the result of a strong cyclonic circulation over south Bengal and the adjoining Bay of Bengal.

A child was electrocuted when he touched a lamp post on Ramesh Mitra Road, which was flooded in the rain. 

Heavy to very heavy rain has been forecast in the city and its surroundings over the next two to three days.

The skies had darkened around 4pm and soon the rain arrived, accompanied by thunder and lightning. The rain  continued in bursts for the next 90 minutes. Parts of Central Avenue, the Park Circus seven-point crossing, Gariahat and many other streets were quickly flooded, adding to the traffic mayhem. 

G.C. Debnath, deputy director-general of the India Meteorological Department in Calcutta, said the current wet spell could be the heaviest of of the monsoon.

WHERE DID IT RAIN THE HEAVIEST?

Jodhpur Park, which received 104mm in just one hour, starting 5pm. This was the most intense shower in the city this season. 

The rest of south Calcutta too received heavy, albeit varying, amounts of rain. Chetla and Southern Avenue recorded 90mm, Garia 89mm and Kalighat 65mm. 

North Calcutta was less affected by the cyclonic circulation, receiving between 3.6mm and 10mm of rain during the same period.

The last spell of heavy rain was on July 25, when the city received 98.6mm. This rainfall was recorded over four hours in the morning and early afternoon.

On Monday, the rain came down in heavy bursts over a much shorter period of time, which explains the instant waterlogging on many thoroughfares.

WHAT IS THE FORECAST 

Heavy to very heavy rain. In meteorological parlance, heavy rain means 64.5mm to 124.4mm while very heavy rain denotes 124.5mm to 244.4mm. The all-time rain record for August is 253mm, which was way back in 1888.

WHAT IS CAUSING THE RAIN

“A cyclonic circulation has formed over Gangetic Bengal and the adjoining Bay of Bengal. This weather system is constantly pumping moisture into land from the Bay of Bengal, leading to cloud formation and rain,” the IMD deputy director-general said.

The rainfall is expected to increase because the system is in the process of intensifying into a low-pressure area by Tuesday. As and when that happens, it will start drawing even more moisture and the intensity of the rain will increase. 

RAIN AND TRAFFIC PAIN

Calcuttans on the move were delayed by the dual impact of rain and crawling traffic on Monday afternoon. Prince Anwar Shah Road, Gariahat Road, Southern Avenue, parts of Central Avenue near Muktaram Babu Street, the Park Circus seven-point crossing and Behala were all inundated within 45 minutes or less of the downpour. 

Rajiv Banerjee, a resident of Ballygunge Circular Road, was stranded in a temple on Ganja Park in Bhowanipore for 40 minutes because of the torrential rain. By the time the rain stopped, traffic had gone haywire.

“Almost all thoroughfares, including Paddapukur, Sarat Bose Road and Ballygunge Circular Road, were  waterlogged. Cars struggled to move and at many places even the steps leading to houses were submerged,” Rajiv said.

A tree each fell on Prince Anwar Shah Road and Chowbhaga, along the Basanti Highway, adding to the traffic woes.

FLOODING ALERT FOR TUESDAY

On Monday, only parts of the city received heavy rainfall and the Hooghly was on low tide at the time, allowing the Calcutta Municipal Corporation to open the drainage lock gates. Yet, there was waterlogging in the city that lasted until many hours after the downpour, which retreated at 6pm.

Calcutta’s drainage system can flush out 6mm of water in an hour if it rains throughout the city.

When a strong weather system like a low-pressure area causes rainfall, it is generally equally distributed.

So, if heavy to very heavy rainfall does occur in the city on Tuesday, many roads might be inundated for longer periods.
The IMD hasn’t issued a flood warning, though.

Reporting by Rith Basu; pictures by Amit Datta