Thanks to the surface-level warming of ocean temperatures, a low-pressure area forming in the Bay of Bengal intensifying into a cyclone has become a common occurrence. Since air moves from high-pressure to low-pressure areas, this depression on the east side lifts moisture-laden winds from the left. It is these moisture-heavy winds passing over Kerala to the east, drawn by the cyclonic formation now seen over the South Andaman Sea, that are now providing the state with intense summer showers.
However, this time, it looks like the summer showers are more copious than ever before. In this halfway period of the three-month (March 1 - May 31) pre-monsoon season, Kerala has recorded the highest ever rainfall in the last 10 years for which figures are available.
From March 1 to April 14, Indian Meteorological Department (IMD) figures show that Kerala has recorded 129% excess rainfall.
All districts, except Thrissur, Palakkad and Thiruvananthapuram, witnessed 'large excess', or more than 60% excess rainfall. The three districts received 'excess' rain, which is rainfall over 30% of the normal.
Kasaragod received the highest pre-monsoon showers, a whopping 569% above normal.
Usually, the northernmost district is the driest patch of land in Kerala during the first half of the pre-monsoon period, receiving only around 25.8 mm of rainfall during the period. This time, the district has received 172.7 mm of rainfall, a 569% increase. Ernakulam and Pathanamthitta have witnessed rainfall that was more than 200% of the normal; 253% and 207% respectively.
Nine of the 14 districts, including Alappuzha and Kottayam where the summer showers hurt the farmers the most this year, received rainfall that was more than 100% excess. The rainfall was so heavy that it destroyed crops in over 12,500 hectares. across Kerala.
However, the IMD officials say that the intensity of the rains could fall by the last week of April, and the average excess rainfall could dramatically come down by the end of May. There are already signs of the formation weakening.
In 2017, for instance, there was excess rainfall of a stupendous 189% in March alone but in April and May there was a massive reduction in rainfall and eventually, by the end of the three-month pre-monsoon period, the average rainfall for the period fell below the normal by 7%.
The heavy summer showers are not unusual either. Last year, 2021, the pre-monsoon showers were excess by 107%. In the last decade, there were four 'excess' years: 2021 (107%), 2020 (7%), 2018 (37%), and 2015 (23%).
Excess rainfall does not foretell anything devastating either. It is not a sign of a drought or a flood to follow. In 2019, when there were heavy floods, there was a 53% deficiency in summer rains. During the year of the deluge in 2018, there was excess pre-monsoon rain but only 37%.
The heavy rains came with its share of advantages, too. Power consumption fell. This year, power consumption in April is 75 million units. Last year same period, the average consumption was 78 MU. At this stage, Kerala's dams have better storage than last year.
Take for instance Kerala's biggest dam, Idukki. Its reservoir has water up to 716.98 metres, which is enough to generate 1048 million units of power. Last year same time, the dam had water to generate only 894 MU.
This year, therefore, KSEB has more natural bounty to play with. Rather than resort to costly purchases from outside, this has allowed KSEB to generate more hydel power for daily needs than last year.
