Monsoon arrival may be delayed this year, predicts IMD

Looming El Nino can cause rainfall deficit, droughts, say experts citing historical data

By Akshit Sangomla
Published: Tuesday 16 May 2023
Typically, El Nino years are associated with delayed monsoons, low rainfall & droughts. Photo: iStock

The southwest monsoon season will set in over Kerala by June 4, 2023 — three days later than usual, the India Meteorological Department (IMD) predicted. 

The forecast came at a time when the spectre of an El Nino event looms on the equatorial Pacific Ocean, which could have a huge impact on the onset and the distribution of rainfall during the season.

The weather agency also gave a model error of around four days, which means that the onset can be as late as June 8. 

There is more than an 80 per cent chance of the development of an El Niño event in the equatorial Pacific Ocean in the May-June-July period, according to the National Oceanic and Atmospheric Administration (NOAA) of the United States. This chance increases to almost 90 per cent for the June-July-August period.

The development of an El Niño may coincide with the onset of the southwest monsoon season, which is the primary rainfall season of India. 

Read more: Delayed monsoon: How a possible El Nino can lead to failed rains in parts of India

The country receives 70 per cent of its annual rainfall during the four-month period (June-September) and a large proportion of its farmers (more than 50 per cent) are still dependent on these monsoon rains for the cultivation of their crops. 

The El Niño is the warmer than the normal phase of the El Niño Southern Oscillation (ENSO) phenomenon and generally leads to less intense rainfall than normal during the monsoon season for India. 

Between 1951 and 2022, 60 per cent of the El Niño years witnessed below-normal or deficient rainfall during the monsoon season, especially during strong El Niño years, according to data from the IMD. India also experienced droughts in many of these years.

The last major El Niño event lasted from September 2014 to May 2016. There were major heatwaves in India and many other countries around the world and a huge impact on the monsoon rainfall in India was observed during the period. 

In 2015, when the El Niño event was at its peak, India received only 86 per cent of its normal monsoon rainfall and the year was officially a drought year for the country. 

In 2016, when the El Niño was in its waning phase India received 97 per cent of its normal monsoon rains which are categorised by IMD as a normal monsoon year.

Meteorologists haven’t ruled out the possibility of extreme rainfall or floods either for the upcoming monsoon. A section of them have also hinted at the development of a cyclone right ahead of the onset, something that is not unusual in case of a delayed monsoon. This may lead to very different outcomes during the season than what is being predicted now.

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