The year 2018 will be best known for the normal to above normal rains the twin monsoons (South-West and North-East) promised, but failed to deliver, despite braving cyclones along the coast and historic floods in the South.
The South-West monsoon (June-September) for the country as a whole delivered 91 per cent of its long-period average (LPA) — or the mean rainfall during the season over the 50-year period from 1951-2010 — against a forecast of 97 per cent (see table).
Hurdle in East
The India Met Department (IMD) attributed the forecast error to the ‘large monthly rainfall deficiency (more than 20 per cent) over North-East India during all four months.’
A poor September for the South Peninsula and Central India was another factor. Seasonal rainfall here over North-East is passing through a ‘below normal epoch’ as during the early 1950s to mid-1980s.
In a review, the IMD said forecasts for the seasonal rainfalls over three of the four broad geographical regions as well as that for the July and August rainfall over the country as a whole had proved correct.
However, those for the seasonal rainfall over the country as a whole and over North-East India and rainfall during the second half of the season over the country as a whole had failed.
The IMD sought to find relief in the analysis at the end of the season that rainfall was ‘reasonably distributed’ across barring East and North-East India.
Good soil moisture
The IMD cited figures from the Ministry of Agriculture data stating that overall Kharif crop acreage was higher by 2.6 per cent as compared to the highest ever acreage/record foodgrain production that the country witnessed in 2017.
This hints largely at the good soil moisture distribution across the country.
Adequate soil moisture available over the northern parts of the country may help the Rabi crops during 2018- 19.
Also, the higher soil moisture over North-East India despite a -25 per cent departure from normal rainfall suggests that whatever rainfall received has been ‘above the optimal requirement for the soil to support agriculture operations.’
The same is true for Jharkhand and Bihar. Reasonably well distributed soil moisture is the primary reason for the good acreage of rain-fed crops (very close to normal for pulses, oilseeds and cereals).
Monsoon ‘choke’ phases
Similarly, the reservoir levels monitored by the Central Water Commission till September 30 was at five per cent higher than 10-year mean storages and 17 per cent higher than the storages of corresponding period during 2017.
The monsoon had faced two critical ‘choking’ phases — an early hiatus materialised on June 13 and lasted 10 days. The next was in August when it lapsed into a ‘break condition during the first week (August 1 to 6).
In between, it covered the entire country on June 29, two weeks earlier than the normal date of July 15. the years 2015 and 2013 had also witnessed its rapid advance over entire country on June 26 and June 16.
The season witnessed a very large number of ‘high impact weather events, of which ‘floods’ were the most frequent and widespread phenomenon.
Almost all meteorological sub-divisions experienced one category or the other.
Extreme weather events
Kerala experienced one of the worst flood situations of the century due to frequent heavy rain spells and several extremely heavy rain events, especially during the first half of August.
The monsoon started its withdrawal from Rajasthan on September 29 delayed almost by a month and exited the South Peninsula only October 21, six days behind normal.
This was enough to delay the arrival of the North-East monsoon over the South Peninsula, exacerbated further by two strong cyclones, ‘Luban’ in the Arabian Sea and ‘Titli’ in the Bay of Bengal. The IMD had forecast a normal to above normal season.
After the North-East monsoon set in on November 2, two more cyclones — ‘Gaja’ and ‘Phethai — popped up but went wayward denying the benefits to the catchment area. Cumulatively, these failed the North-East monsoon by a large margin.