For Keralites, it is Edavapathi, the rains that come in the middle of the Malayalam month of Edavam. The arrival of the southwest monsoon over this southern State is an event greeted with unalloyed joy and relief right across the country. The rain-bearing clouds will, in due course, make their way north, bringing to an end the unremitting heat of summer. There is hope too that the rains will lead to a bountiful harvest, thus lending an extra bounce to the economy. This year, the rains reached Kerala five days later than the long-term average date of June 1. It must be borne in mind that the date of onset is highly variable. The earliest it occurred was on May 11 (in 1918) and the most it was delayed was till June 18 (in 1972). Moreover, the date of onset is not quite an indicator of how the rainy season will shape up. Although the southwest monsoon came three days earlier than normal in 2002, that year saw a severe drought. In 1983, on the other hand, the monsoon got to Kerala almost two weeks late, but nevertheless went on to provide a surfeit of rain in the months that followed.

Mariners of yore knew and made use of the change in winds that preceded the monsoon. Strong winds blowing across the Arabian Sea are a prerequisite for transporting the vast amounts of moisture needed to sustain the huge girdle of thick clouds that provide rain over India. Sufficient levels of wind blowing from the west is among the criteria that the India Meteorological Department uses to determine monsoon onset. This year, although the winds meet those requirements, there is nevertheless concern that they have not grown powerful enough, and that the progress of the monsoon northwards might falter. The rains typically ought to reach much of the country by the end of June and the remaining parts by mid-July. However, the waters in the central and eastern parts of the equatorial Pacific Ocean have been warming rapidly and showing signs of turning into a full-fledged El Niño. A developing El Niño phenomenon can take its toll as the monsoon establishes itself over the country. If that happens this year, rainfall in June, which is essential for several crops, could be affected. A bigger worry concerns the larger impact that an El Niño might have on the monsoon. While most of the severe droughts over India have occurred when there was an El Niño, only about 43 per cent of the El Niño events that occurred over 126 years (from 1880 to 2005) resulted in deficient monsoon rains. Although all the indications are that an El Niño is indeed brewing this year, it is not clear as yet how strong it might turn out to be or how much impact it could have on the monsoon. Hoping for the best and preparing for the worst is perhaps the best strategy.

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