A powerful thunderstorm swept across Kolkata on Thursday evening, sending flowerpots flying from balconies, lighting up the sky with frequent lightning and bringing traffic to a standstill in several parts of the city, even as the monsoon’s withdrawal from south Bengal appeared to slow.
The India Meteorological Department recorded only 2.6mm of rain in Alipore until 8.30pm. The reading, however, did not reflect conditions across the city, where several areas experienced significantly heavier showers. Blinding rain reduced visibility and disrupted traffic during the evening, while gusty winds added to the hazards on roads and around buildings.
The storm arrived on October 8, the usual date for the monsoon’s withdrawal from south Bengal. The Met Office said the southwest monsoon had resumed its retreat on Thursday after the withdrawal line had remained stalled over parts of the heartland, including Jharkhand, because of multiple weather systems.
According to a Met report, the monsoon had further withdrawn from the remaining parts of Maharashtra and from some parts of Goa, Karnataka, Telangana and Odisha, as well as additional areas of Jharkhand and Chhattisgarh. Conditions were becoming favourable for its further withdrawal from parts of eastern India, the northern peninsula and large parts of northeast India over the following three to four days.
The weather systems influencing the region were also contributing to the storm over south Bengal. An upper-air cyclonic circulation was present over northeast Bihar and neighbouring areas, while a trough extended from the circulation towards Telangana, passing across Jharkhand, Odisha and Chhattisgarh. Met officials said these systems were feeding moisture into south Bengal, where it interacted with heat to produce thunderstorms.
The contrast between the Alipore measurement and the heavier rain reported elsewhere highlights how uneven storm activity can be across Kolkata. A relatively low reading at one observatory did not prevent intense showers from affecting other parts of the urban area, particularly during the evening traffic period. The result was a citywide disruption that varied sharply from one locality to another.
The storm also exposed the immediate safety risks associated with strong pre- and post-monsoon weather in a densely built city. Flying objects from balconies, lightning and sudden reductions in visibility created hazards for pedestrians, motorists and people travelling through exposed areas. The source report did not provide details of injuries, structural damage or power outages.
The Met Office expected the rain to subside from Saturday. It said there was no rain warning for October 10 to 13, indicating that the intense weather was expected to ease after the current spell. Further withdrawal of the southwest monsoon from eastern India will depend on the movement and weakening of the weather systems influencing the region.
