The skies opened over Jharkhand for four hours since Tuesday midnight, following a depression over the Bay of Bengal, and triggered torrential rain in southern parts of the state including Jamshedpur and its adjoining areas.

The IMD observatory in Sonari recorded 219.4mm rainfall, the highest in the steel city in eight years. Statistics show that on June 18, 2008, the day monsoon arrived in Jharkhand that year, Jamshedpur had registered 338mm, the heaviest on a single day and the highest ever in the whole of Jharkhand. Data further revealed that Wednesday's 219.4mm is a record in August, the third month of monsoon.

In Met parlance, "heavy rain" translates into 64.5mm to 124.4mm on a single day while "very heavy rain" means 124.5mm to 244.4mm. "Extremely heavy rain" refers to 244.5mm or more.

"Never before has Jamshedpur or any other part of Jharkhand recorded so much rain on a single August day. The rain was accompanied by lightning and thundershowers," said A.K. Sen, the director of Patna Meteorological Centre.

Taking the bounty into account, the steel city has notched 472mm in the past 10 days. The cumulative figure so far since June suggests that against a normal of 643.2mm, East Singhbhum district has recorded 904 mm, a surplus of 41 per cent.

The depression over northwest Bay of Bengal moved north-eastwards and intensified into a deep depression on Wednesday. Several parts of northeast Jharkhand such as Sahebganj, Dumka, Godda, Pakur and Deoghar received moderate rainfall between 40mm and 50mm. Weathermen clarified that the depression did not impact weather conditions in capital Ranchi and its adjoining districts.

Director of Ranchi Meteorological Centre B.K. Mandal said the deep depression was likely to weaken gradually and move north-westwards.

Both Patna and Ranchi IMD centres extended the forecast of heavy rain in isolated pockets in the next 48 hours. "Downpour is expected in some places of northwestern and southern Jharkhand," said a senior Met official in Ranchi.

The depression, coupled with an active monsoon trough, resulted in a shower showdown at many other places apart from Jamshedpur. Over 80 per cent IMD observatories reported moderate to heavy rainfall in the past 24 hours.

Rajdhanwar in Giridih district soaked in 110mm while Giridih town recorded 65mm. Ghatshila in East Singhbhum, Dhanbad and Chatra registered around 40mm each. Chakradharpur in West Singhbhum and Dumka experienced around 50mm.

Met data shows that Jharkhand has received 514.2mm rainfall so far against a normal average of 648.7mm, a deficit of 21 per cent, two per cent less than last week. The deficit margin is expected to narrow in another 48 hours.