A torrential two-hour downpour from Saturday noon inundated large parts of the city, uprooted trees and slowed down traffic on waterlogged roads that were already pockmarked with potholes.

Vehicles crawled along many roads that remained underwater till at least the evening.

Harish Mukherjee Road, Southern Avenue, Beckbagan Row, Gariahat Road, CR Avenue, Syed Amir Ali Avenue, Sarat Bose Road, and Boroj Road were all waterlogged.

An official of the Kolkata Municipal Corporation (KMC) said: “It rained relentlessly for two hours. Had the rain been spread over a longer duration, waterlogging could have been prevented.”

Twin troughs

The Alipore Met office also classified the downpour as “heavy rain”. According to the IMD bulletin issued in the evening, 84mm of rain was recorded in Alipore. In Met parlance, rainfall over 60mm in 24 hours is categorised as heavy.

The Met office had forecast only light to moderate rain for Saturday. But a combination of factors led to the excess. “The monsoon trough, along with another trough running from central north Bihar to Odisha across Jharkhand, aided in cloud formation,” said an IMD official.

“The morning was sunny and hot. The moisture incursion led to the formation of strong thunderclouds over Calcutta, resulting in the heavy rain,” the official said.

Light to moderate rain is likely on Sunday.

Travel woes

Many commuters were stranded as the rain lashed the city. Those in cars said it took them almost twice the usual time to reach their destinations.

A Jadavpur resident who had gone to a café near Vivekananda Park on Saturday afternoon said the return journey took double the usual time. A woman who travelled from Chandni Chowk to Jodhpur Park said it took her nearly two hours.

Rai Bhose, who went to Jatin Das Road, off Sarat Bose Road, just as the rain started, said the road was already waterlogged. “When I opened my car door, water gushed in,” she said. Bhose managed to start the engine and drove on, but near the Lake Gardens flyover, she noticed a burning smell. “I stopped my car and walked back home,” she said.

A resident of Prince Anwar Shah Road said water had entered the parking area and elevator shaft of their apartment building. The elevator had to be shut down. The road in front of South City Mall was also flooded.

Trees fall, roads flooded

Uprooted trees blocked stretches of Southern Avenue and added to traffic delays. Police had to divert all traffic to the Tollygunge-bound flank after a tree fell across the Golpark-bound flank near Nazrul Mancha. An officer said the approach to Dhakuria Bridge from Golpark remained underwater till the afternoon.

A tree fell inside Chetla Boys School, breaking its boundary wall. Another fell on Cornfield Road.

“At least six trees fell. Our teams are working to remove them,” a KMC official said in the afternoon.

Long stretches of CR Avenue were under water. “The stretch between Sovabazar and the Beadon Street-Central Avenue crossing had water along the roadsides. The roads running perpendicular to Central Avenue were also inundated,” said a Sovabazar resident.

Another stretch of CR Avenue — between Ram Mandir and the School of Tropical Medicine — remained flooded for several hours. Ramkanto Bose Street was also waterlogged in the afternoon.