Cyclone Nivar storm, rain may hit agriculture across south India

Agriculture in the five states of south India could be affected due to Cyclone Nivar that is now expected to hit the region during the late midnight hours of November 25 or the early hours of November 26, 2020.

The primary concern for both, the administration as well as farmers are storm surges, apart from the high wind speeds that might uproot a lot of trees along the coast and the inland areas. A ‘storm surge’ is the rise in sea level along the coast after a cyclone makes landfall.

The India Meteorological Department (IMD) has predicted that the storm surge will be up to 0.9 metres above sea level.

For stronger storms, this rise may vary from 1-6 metres. Even in the case of Cyclone Nivar, the storm surge might be higher than what has been predicted by IMD.

Storm surges can affect agriculture as they bring saline sea water into farmlands, causing long-term impact on soil quality. This, in turn, can affect agricultural production.

The very severe Cyclone Gaja had similarly caused much distress to Tamil Nadu farmers in November 2018, from which they have still not been able to come out entirely.

Agriculture might also be impacted in the short term in the states of Tamil Nadu, Karnataka, Andhra Pradesh, Telangana and some parts of Kerala due to the wind speeds and heavy rainfall that would be brought in by cyclone Nivar.

The wind speeds will majorly affect coconut farms and other fruiting trees along the coast and inland.

The rabi cropping season in these states will bear the brunt of the flooding, flash flooding and water logging from the rainfall. In Tamil Nadu, rice, pulses and coarse cereals are sown in almost one lakh hectares and in Andhra Pradesh, these crops are sown in close to 1.5 lakh hectares.

Wheat, pulses and coarse cereals are also sown in over a lakh hectares in Karnataka. Much of this cropped area is now under threat from the impacts of the cyclone.

Landfall time

The cyclone’s time of landfall has changed thrice since November 23 — from the afternoon of November 25 to late evening on the same day to night and now midnight.

This means that the cyclone is approaching the coast much slower than predicted and will pick up more and more moisture and energy from the currently warm sea waters (29-30 degrees Celsius) of the Bay of Bengal.

This might also mean that the cyclone might travel much further inland causing destruction with rainfall and high wind speeds.

The IMD says that the cyclone lay over the sea as a severe cyclone as of 11:30 am November 25 and was moving at a speed of around 11 kilometres per hour (kmph) over the sea surface.

This is a significant improvement over its November 24 speed of about 5-7 kmph but a close watch is to be maintained on its movement.

The storm will initially move in a west northwestward direction and then in a north westward direction to hit the coast.

The expected location of the landfall is along the Tamil Nadu coast, between Karaikal and Mahabalipuram.

The wind speeds are likely to be in the range of 120-130 kmph, with gusts of up to 145 kmph at the time of landfall.