An intense squall with a speed of 88 kmph swept through Kolkata on Friday afternoon, bringing much-needed relief as the temperature plummeted by 7 degrees Celsius. The season's most powerful nor'wester, accompanied by heavy rain and thunderstorms, also left a trail of destruction across the city.
Sequence of Events
The morning started sunny, but dark clouds began gathering around 2 pm. Shortly after the India Meteorological Department (IMD) issued a red warning for Kolkata and neighboring North and South 24 Parganas, the nor'wester struck at around 2:40 pm. Alipore recorded the squall from the northwesterly direction at a maximum speed of 88 km/h, sustained for at least two minutes between 2:45 and 2:47 pm. Earlier, another squall hit Dum Dum from the same direction at 74 km/h.
Temperature and Rainfall
The mercury dropped instantly by 7°C within an hour, from 34°C to 27°C. Alipore recorded about 40 mm of rainfall during the hour-long spell. Some parts of the city experienced brief waterlogging, and traffic was affected where trees fell on major roads. Met officials expect a further dip in temperature by Saturday.
“This was the most powerful squall of the season. At 88 km/h, it was very potent and destructive, strong enough to uproot trees. Highly intense thunderstorm cells and dense clouds caused the sharp spell and gusty winds,” said HR Biswas, head of IMD’s Regional Meteorological Centre Kolkata.
Monthly Rainfall Records
The 40 mm rain is the highest single-day rainfall this May. The total monthly rainfall in May has reached about 165 mm, surpassing the normal of 118 mm. Kolkata has recorded rain on 11 days this May, against a climatological normal of 6.2 rainy days.
North-South Divide in Rainfall
Data from Kolkata Municipal Corporation (KMC) drainage pumping stations showed a north-south divide, with south Kolkata receiving heavier rainfall. Jodhpur Park recorded the highest hourly rainfall of 68 mm between 1:45 pm and 2:45 pm. Other stations like Ballygunge (50 mm), Kalighat (51 mm), Kudghat (52 mm), Mominpore (42 mm), and Behala Flying Club (53 mm) made drainage difficult. Heavy-duty pumps operated continuously.
Residents of Amherst Street, Keshab Sen Street, Thanthania, College Street, and Bidhan Sarani faced waterlogging due to construction of a drainage pumping station at Hrishikesh Park.
Outlook
“We can expect some rain on Saturday, but with only 40% probability, so even if it rains, it will be less intense,” Biswas added.
