A spell of rain, accompanied by gusts of wind that uprooted trees and streaks of lightning, struck Calcutta and the surrounding districts on Monday night.
The showers were the sharpest in many months in the city after it experienced one of the driest winters.
A Met official said it was a thunderstorm, one of several to strike Bengal on Monday.
Around 8.45pm, the Met office issued a thunderstorm alert for Calcutta, Howrah, East Midnapore and South 24-Parganas. Besides light to moderate rainfall, winds blowing at over 70kmph were on the radar, the alert said.
The showers started shortly after 9pm. People were seen huddled under flyovers and any other shade they could manage.
Around eight trees were uprooted, or their branches fell on roads. A KMC official said the civic body received calls of trees or their branches falling at Behala, Jadavpur and Monohorpukur Road.
"A tree fell on a parked car in front of a sweet shop in New Alipore. No one was injured," said a KMC official.
An active Western Disturbance is behind the current spell of thunderstorms across the state.
Dum Dum experienced a squall with a highest wind speed of 50kmph between 7.30pm and 7.31pm on Sunday. Multiple districts received formidable rain. Many areas in north Bengal received heavy rain. Some north Bengal districts received hailstorms.
On Monday, thunderstorms were also reported in the districts of south Bengal. Districts like Bankura, Purulia, Birbhum and West Burdwan received sharp spells.
"A Western Disturbance is active from the western Himalayas to Sikkim. In the presence of a favourable wind pattern at lower levels and strong moisture incursion from the Bay of Bengal, enhanced thunderstorm activity is very likely over the districts of Bengal," said a Met bulletin issued on Monday afternoon.
Western Disturbances are extra-tropical storms that bring rain and snow to the northwest and northern Himalayan states. The storms travel from west to east. A powerful Western Disturbance can also cause rain and snow in Sikkim and the upper reaches of Darjeeling.
Light rain or thundershowers are likely in North 24-Parganas, South 24-Parganas, Nadia, Murshidabad, Birbhum, Jhargram and West Midnapore districts of south Bengal on Tuesday. The showers are likely to be accompanied by moderate gusts of wind.
In north Bengal, Darjeeling, Jalpaiguri, Kalimpong, Cooch Behar and Alipurduar are likely to see rain and winds on Tuesday. The intensity is likely to be less than that of the past couple of days, said a Met official.