Flood risk may re-emerge as rains head back to North-East

Water levels in rivers of Assam and Meghalaya have started reducing with the intensity of rainfall, but these flood-hit states may have to reckon with a renewed threat since the monsoon trough may bring back its tail to lash the foothills of the Himalayas from July 26.

It could also drag along with it heavy monsoon rains, which had caused severe to extreme flooding over the region earlier last week.

The swing and back and forth of the monsoon trough in this manner needs to be watched closely since it could presage drastic change in weather to its either side (South and North). A northward shift, as happens from today, brings the active belt of rain to the foothills and adjoining East and North-East India while the swing back to the South relieves the region of the extreme wet conditions.

Heavy to very rain likely

The India Meteorological Department (IMD) has forecast isolated heavy to very heavy rainfall to come back to Assam and Meghalaya from today. Brahmaputra is currently flowing in severe flood condtions and is rising in Dhubri district while falling in Jorhat, Sonitpur, Kamrup and Goalpara. The current reduction in rain intensity may relieve these conditions from Dibrugarh to Dhubri only for the next 2-3 days.

The situation may change since the rains are forecast to scale up from today with implications for rivers in the North-East India, a bulletin from the Central Water Commission (CWC) said. So too in Bihar, Jharkhand and plains of West Bengal where River Gandak has currently fallen from extreme flood to severe flood situation and may briefly fall further with the reduction in rainfall.

In Uttar Pradesh, River Ghaghra is flowing in a severe flood situation at Ballia and River Rapti is in spate Gorakhpur. Strict vigil needs to be maintained in all the above states and districts for the next 2-3 days, the CWC said. The heavy monsoon rain has now delivered a cumulative surplus of 46 per cent for Assam till date (June 1-July 25). Nagaland, Manipur and Mizoram have retained a deficit while Tripura is now just about normal.

Some states in deficit

Elsewhere, rain-deficit conditions have continued over parts of North-West India including in Jammu & Kashmir, Ladakh, Himachal Pradesh, and Rajasthan. Rains are now expected to arrive over these regions with the shift of the monsoon trough to the North. The other rain-deficit regions are the Union Territories of Dadar & Nagar Haveli and Daman & Diu in West India and Kerala in the South.

Meanwhile, both IMD and the global weather models are scanning the Bay of Bengal, so far a graveyard for cyclonic circulations, for fresh signs of life towards the end of this month. A cyclonic circulation is likely in the making here that could go on to intensify and earn spurs as a long-awaited low-pressure area. If this forecast holds, the system could change the complexion of the monsoon over the West Coast and Central India.

It could also give it a rousing start for the monsoon early into August, which, as per most model forecasts, may deliver above normal rain for most parts of the country. June was good in parts while July has so far failed to deliver to the fullest. August and September would have to come up with more than their quota to justify IMD’s updated seasonal rainfall outlook of 102 per cent for the June-September season.