Bihar could qualify for meteorological drought if the southwest monsoon does not gain steam within the next 10 days.
The rainfall deficiency in Bihar stands at 23 per cent at present. Meteorological drought is declared in a state when the precipitation deficiency is 30 per cent or above.
The overall rainfall deficiency in the state has come down from 32 per cent in June to 23 per cent in July. But the shortfall for Patna has surged from 16 per cent to 48 per cent in the same period.
The cumulative rainfall deficiency of 23 per cent till July end this year is less than the previous year but slightly more than 2012. The cumulative rainfall deficiency in end-July in 2013 stood at 29 per cent. The shortfall stood at 22 per cent in 2012.
The state received 262mm rainfall in the past 31 days against the normal precipitation of 343mm, leaving a deficiency of 21 per cent. Patna, on the other hand, received 179mm rainfall in July — fourth lowest for the decade.
Weathermen claimed that the there was no pre-monsoon shower this year and the rain started only after the onset of southwest monsoon in the state on July 18. They attributed the deficient rainfall across the state in July to the unfavourable position of the monsoon trough line.
“Bihar receives good monsoon rainfall when the trough line passes across the state. But it passed through lower altitudes in July, mostly over Odisha and Jharkhand. Normally, north-eastern parts of the state receive good rainfall because of the position of the trough line over foothills of Himalayas but this time south-east Bihar experienced comparatively good rainfall because of the trough line’s position,” said Ashish Sen, director, Patna Meteorological Centre.
According to the records available with meteorological centre, only seven out of 38 districts have shown normal monsoon rainfall figures (+/-19 per cent) till July 31. Total 24 districts received deficient rainfall (-20 to -59 per cent) during the same period. Three districts — Buxar, Arwal and Saharsa — received scanty rainfall, recording a deficiency 60 per cent and above. The highest shortfall has been observed in Buxar with 79 per cent less than normal rainfall till date.
In the entire country, only Odisha (2 per cent) and south Karnataka (1 per cent) have received more than normal monsoon rainfall till date. Twenty-one of the 36 meteorological subdivisions in the country have received deficient rainfall. As on July 30, the average monsoon deficiency in the country stood at 23 per cent.
Met experts cited the possible El Nino effect as one of the factors leading to deficient rainfall across the country, including Bihar. “The monsoon current has been mostly weak this year because of El Nino effect. As a result, the cloud formation is also extremely localised and these are not typical monsoon clouds. Thus, deficient rainfall conditions are being observed across the country,” said Pradhan Parthsarthy, secretary, Bihar chapter of India Meteorological Society, and professor at Central University of Bihar.
IMD earlier predicted that there are more than 70 per cent chances of El Nino weather phenomenon hitting monsoon in India this year.
Patna Met office has given forecast of light to moderate rainfall across the state between August 3 and 6. “Many parts of Bihar are expected to receive light rainfall on August 3, followed by light to moderate rainfall from August 4 to August 6. We are expecting the rainfall because the monsoon trough line is expected to pass through Bihar during that time,” said Sen. He claimed that the state could receive normal or 10 per cent less than normal rainfall in August.