The Met department said the squall lasted for three minutes.
At least three people were killed, many trees were uprooted and suburban train services were affected as nor'wester hit several southern districts of West Bengal on Monday evening, officials said.
A 12-year-old girl was killed after she came in contact with a dangling live wire that got torn during the squall in Botanical Garden area in Howrah city, police said.
A 65-year-old man was killed when his kutcha house collapsed during a thunderstorm in Amsha village in Uluberia police station area in Howrah district, a senior police officer said.
Another 40-year-old woman was killed in Urfuli village in Bagnan police station area in the same district when a tree fell on her during the storm, he said.
The Met department said the squall, recorded at its Alipore observatory in Kolkata, lasted for three minutes from 5.41 pm and had a maximum wind gust of 84 kmph.
Besides Kolkata, the nor'wester hit other south Bengal districts including Purulia, Bankura, Birbhum, Purba and Paschim Medinipur, Purba and Paschim Bardhaman, Howrah, Nadia and South and North 24 Parganas, the weatherman said.
Light to moderate rain accompanied the squall in various districts, including in Kolkata, it said. Hundreds of passengers got stranded at various stations of the suburban train services connecting Kolkata with neighbouring towns as the nor'wester hit during peak office hours.
A large number of people were seen waiting for trains to their destinations from Sealdah, one of the busiest stations in the state.
Train movement in different sections of Eastern Railway's Sealdah division were affected since 5.40 pm as broken tree branches fell on overhead wires and railway tracks, an official said.
Suburban train services were affected between Shyamnagar and Naihati in Sealdah main section and between Baruipur and Lakshmikantapur in Sealdah south section, he said.
In the Circular Railway of ER, a tree branch fell on the railway line near BBD Bag station, he said.
Tower vans were dispatched to restore services as early as possible, the official said.
In the ER's Howrah division, tree branches fell at Chandannagar and foreign bodies got entangled with overhead wires at Konnagar.
"Train movement in Howrah-Bandel section was, however, maintained via reversible line which was unaffected," he said.
In the Howrah-Kharagpur section of the South Eastern Railway, train services were more or less unaffected except stoppages for about five to ten minutes at one or two places due to the nor'wester, an SER official said.
The squall brought down a number of trees in Maidan area near Victoria Memorial and in Lake Gardens area in south Kolkata, damaging a few cars.
Disaster Management Group personnel were deployed to remove the felled trees and clear the roads.
The nor'wester, which occurred during peak hours in the evening, caused heavy traffic snarls in the city, as felled trees blocked roads in some places.
In Jhargram district, roofs of several kutcha houses were blown away in the wind and many trees were uprooted, prompting minister Birbaha Hansda to visit the affected areas.
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