IMD: seawater surge a result of Ockhi’s proximity to Goa coast





The path of the very severe cyclonic storm ‘Ockhi’ was parallel to the west coast and came closest at a distance of just 200-300 kilometres away from the Goa coast since Sunday. As a result, the coastal parts potentially experienced strong, damaging winds, rise in the sea level, coastal flooding and beach erosion.

“There is absolutely no threat from the cyclonic storm to the state and it will not make a landfall in the state, as it has recurved south southwest. However, the storm surge is due to the severity of the cyclone and its close distance from the state which was around 200-300 kilometres,” an India Meteorological Department (IMD) official said.

Storm surge, according to the IMD, is an abnormal rise in water generated by a storm, over and above the predicted astronomical tides. The rise in water can cause extreme flooding in coastal areas particularly when storm surge coincides with normal high tide. Storm surge is created when strong winds from the storm push water toward the shore.

Although cyclones affect the entire coast of India, the east coast is more prone compared to the west coast. The state of Goa is on the west coast, according to National Cyclone Risk Mitigation Project (NCRMP).

An analysis of the frequencies of cyclones on the east and west coasts of India during 1891-2002 show that nearly 308 cyclones (out of which 103 were severe) affected the east coast. During the same period, 48 tropical cyclones crossed the west coast, of which 24 were severe cyclonic storms.

Out of the cyclones that develop in the Bay of Bengal, over 58 per cent approach and cross the east coast in October and November. Only 25 per cent of the cyclones that develop over the Arabian Sea approach the west coast.

However, Goa has never experienced a threat from cyclones in the recent past. The extremely severe cyclonic storm ‘Nilofar’ was, at the time, the third-strongest cyclone, that hit in November 2014 in the Arabian Sea and moved initially north-northwestwards for two days and then recurved northeastwards towards north Gujarat and adjoining Pakistan coast but did not affect the Goa coastal line.

Similarly in August 2015, the tropical cyclone called ‘Ashobaa’ had intensified into a cyclonic storm about 590 km west southwest of Mumbai which was far away from the Goa coast without posing a threat. The weather system headed north and affected Oman and Persian Gulf.