An overcrowded bus moves through a waterlogged road following rain, in Kolkata.
Credit: PTI photo
New Delhi: Dense layers of clouds with a height of 5-7 km brought extremely heavy rainfall in Kolkata—heaviest in the last 39 years—in the wee hours of Tuesday inundating the eastern metropolis a few days ahead of the annual Durga Puja extravaganza.
The India Meteorological Department recorded more than 251 mm of rainfall in Kolkata in the last 24 hours, over 95 per cent of which occurred between 1130 PM on Monday to 0830 am on Tuesday.
This included a three hour spell between 230-530 AM when the sky opened up over the City of Joy bringing 185.6 mm of rainfall.
Early morning on Tuesday (between 3-4 am), the city received 98 mm rainfall within an hour in a close resemblance of a cloudburst situation though the amount of rainfall received is marginally short of the IMD’s definition of a cloudburst. The weather agency defines cloudburst as 100 mm or more rainfall within an hour.
“Kolkata Doppler weather radar image showed high moisture content persisting over the Kolkata area with cloud height about 5 to 7 km,” an IMD scientist told DH.
A low-pressure zone formed on the morning of Sept 22, which slowly moved to coastal areas of Gangetic West Bengal and adjoining north Odisha and north west Bay of Bengal next morning. Under its influence strong moisture convergence persisted over Kolkata and neighbourhood areas.
The rainfall was the highest since 1986 and sixth-highest single-day rainfall in the last 137 years, only behind the record rainfall of 369.6 mm in 1978; 253 mm in 1888; and 259.5 in 1986.
IMD officials said similar weather conditions would continue Tuesday after which they might be “less marked”. But light to moderate thunder showers are likely in south Bengal for the next four days, dampening the puja celebrations.