While some districts such as Assam’s Dhemaji and Dibrugarh received excess rainfall, others in Manipur and Mizoram are reeling under deficit
The North East India has been reeling under a worrying weather trend: Prolonged periods of no rainfall, followed by sudden bouts of rain, sometimes with an overall rainfall deficit.
The most recent case is that of Assam, which is experiencing a second wave of floods caused by incessant rainfall on June 23, 2020. The first wave was end-May 2020. According to a situation report by the Assam State Disaster Management Authority, one person died and 37,675 people were affected as on June 24.
The North Eastern states have been receiving less rainfall than normal for several years and the distribution pattern is skewed. In 2019, the region recorded a deficit of 12 per cent while the rest of the country had an excess rainfall of 10 per cent — the highest in the last 25 years.
The intense activity of southwest monsoon season in the region is behind the floods this year in Assam. The activity will continue for the next few days and other northeastern states might also experience a flood-like situation.
According to the India Meteorological Department (IMD), there are two reasons for the intense monsoon activity. First, the northward shift of monsoon trough that runs from north Punjab to northwest Bay of Bengal. Monsoon rains are generally clustered around such troughs.
Second, the coming together of strong winds from the south and southwest directions carrying moisture from the Bay of Bengal.
The floods impacted five districts in upper Assam the most — Dhemaji, Jorhat, Majuli, Sivasagar and Dibrugarh. The situation in Dhemaji is the worst — the flood affected 61 villages, destroying crops over 3,474 hectares and impacting over 15,000 people there. At least 12 roads were damaged.
Dhemaji received 86 per cent excess rainfall on June 23 that soared to 163 per cent on June 24. Between June 1 and June 24, the district received 150 per cent more rainfall than normal.
Dibrugarh is the second-most affected district: Over 10,000 people were affected by the floods there. It recorded 129 per cent excess rainfall on June 23 that more than doubled to 273 per cent on June 24. Among other districts that received heavy rainfall were Tinsukia and Baksa, which received 646 per cent and 487 per cent more rain than normal for this time of the year.
Several districts of Arunachal Pradesh too recorded significantly high rainfall and may experience floods in the coming days. The lower Dibang Valley district received 528 per cent excess rainfall on June 24 and 233 per cent excess rainfall on June 23.
The cumulative rainfall for the district between June 1 and June 24 was 133 per cent. The rain on June 24 alone increased the cumulative rainfall excess by 18 per cent. Six other districts in the state have received rainfall more than 100 per cent of the normal.
At the same time, many other states in the North East are suffering from huge rainfall deficit. The situation is highly severe in Mizoram; it recorded a deficit of 55 per cent than normal rainfall.
Manipur recorded 44 per cent less rains than the usual; Meghalaya a deficit of 11 per cent.
Even within states that have received rainfall, the distribution among districts is skewed. While some districts received excess rainfall, others are reeling under deficit.
For instance, while five Assam districts are suffering from floods, 12 recorded deficit rainfall of 10 per cent or more. The highest among these is Darrang that received 83 per cent less rainfall than normal between June 1 and June 24.
According to an IMD report from 2019:
During 18 of the last 19 years (2001-2019), North East India has received seasonal rainfall less than normal with an exception of 2007 (110 per cent of normal).
“This indicates that the seasonal rainfall over North East India is passing through a below normal epoch like it was during early 1950s to mid-1980s”, according to IMD.
In a research paper published in Current Science journal in 2011, scientists had predicted that climate change will affect agriculture, water availability and forests in the North East India. The number of drought weeks during monsoon months in Arunachal Pradesh, parts of Assam, Meghalaya, Mizoram, Tripura and Manipur will increase by 25 per cent in the future, according to scientists.
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