Kolkata drenched in historic downpour, city records third-wettest September day since 1978

Kolkata woke up to sheets of rain and streets turned into rivers on September 23 as the city logged its third-highest single-day rainfall in September since 1978 — an extraordinary 251.4 mm in 24 hours. The deluge, which lashed the city and its suburbs, fell just short of a cloudburst, the Indian Meteorological Department (IMD) confirmed.

Between 2.30 am and 5 am, the skies opened with a furious intensity, unleashing nearly 185 mm in less than three hours. At its peak, rainfall touched 98 mm in an hour—just shy of the 100 mm threshold that would have officially classified the event as a cloudburst.

“This was an exceptionally intense spell caused by a low-pressure system drawing heavy moisture into Gangetic West Bengal,” said a senior IMD official. Radar images showed towering clouds rising 5–7 km high, feeding the downpour.

The city’s tally ranks behind only two earlier September torrents — 369.6 mm in 1978 and 259.5 mm in 1986—and stands as the sixth-wettest day on record across all seasons.

Mayor Firhad Hakim called the flooding “unprecedented,” pointing out that even areas near Adiganga canal, known for quick drainage, were submerged. “The canal overflowed, blocking natural runoff and flooding entire neighbourhoods,” he said. Authorities rushed to open schools as makeshift shelters, providing food and refuge for those displaced from low-lying areas.

Fishermen have been barred from venturing into the Bay of Bengal until September 27, with IMD warning of squally seas. Another low-pressure system is forecast to form over the Bay on September 25, which may intensify into a depression and bring fresh rainfall to South Bengal and Odisha later this week.

Officials stressed caution in the days ahead, urging residents to stay away from trees and electric poles during storms. For now, the deluge may take a brief pause, offering hope that Kolkata’s streets will clear before the Durga Puja festivities.