The great August betrayal & monsoon havoc in Kerala

If the flood situation in Kerala has turned alarming like never before it is because August has turned wayward for the first time in history. The month had, from time immemorial, and without fail, functioned as the great monsoon stabiliser.

August, in other words, was considered the conductor of the monsoon orchestra. If the monsoon is heavy during June and July, August it seems could guide the rain-making instrumentalists to play softly, and vice versa. Take for instance 2013, when the sustained intensity of the southwest monsoon was comparable to this year's. There was an excess rainfall of 50-70 per cent across the state during June and July. But within two weeks of August, the average excess for the season was lulled to 25 per cent. During 2013, though the rain was more intense in most northern parts and more evenly spread than this year, no dams except Idamalayar had to lift their shutters.

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But this time, August had dumped its conductor's baton and walked off. Hell broke loose. The monsoon has acquired what has been termed a 'weird' vigour this month, even greater than in June or July. If the excess was between 20 and 25 during June and July, by the middle of August it has swelled to over 30 per cent.

“In 2013, too, Idukki had witnessed heavy rainfall during August, it was in excess of 30 per cent. But the surge was limited to Idukki. In most other districts, especially in Ernakulam and the northern parts, the monsoon had virtually dried up during August,” a top India Meteorological Department (IMD) official said.

The August rising

This time, the opposite is happening. All districts are witnessing an unprecedented scale up of intensity in August.

In Alappuzha, August has seen an excess of 20 per cent rainfall. (In 2013, there was a deficit of 29 per cent in August). In Ernakulam, there is a 35-40 per cent excess this month. (In 2013, the August deficit was 7 per cent). Kannur, where the intensity is relatively less, has also shown an excess of 10 per cent. (In 2013, the August deficit was 22 per cent). The rainfall intensity in Kozhikode is inching towards an excess of 40 per cent, a peak witnessed in early June. (In 2013, the August deficit was 22 per cent.) Malappuram, too, now shows a 40 per cent excess in Augsut. (In 2013, the August deficit was 11 per cent). In Palakkad the excess is 60 per cent this August. (In 2013 August, the deficit was 16 per cent). In Pathanamthitta, the excess this August has crossed 30 per cent. (In 2013 August, the deficit was 20 per cent). Wayanad, which traditionally gets heavy rain, too has shown a huge deviation from normal during August. The excess is now nearly 20 per cent. (In 2013 August, the deficit was 30 percent).

Kerala still rain-tolerant

If August plays true to nature, it can be said that Kerala will continue to retain its famed tolerance for rains. “It still holds true that Kerala cannot be as easily ravaged by floods the way Mumbai or Chennai or Bengal can be,” said Manoj N, a scientist at Cochin University of Science and Technology (CUSAT).

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Mumbai flooded up disastrously in 2015 when it received 46.8 cm of rainfall in 12 hours in August. Chennai too suffered its worst floods in 2015 when the city recorded 104 cm of rainfall in two days in November. Kerala watered up only after it was pounded by nearly as much volume of rain almost consistently for over 60 days. There were innumerable areas in the state that had been receiving over 25 cm of rain daily. On an average, almost the whole of state, except Kasaragod, had been getting 15-20 cm of rain a day since June. The maximum rainfall Kerala had received this season was 40 cm on August 9 in Nilambur (Malappuram).

This year, from June 1 to August 15, Kerala has received 210 cm (the normal for this stretch is 160.7 cm). Except for Kasaragod, all the other districts have received excess rainfall. Idukki had excess rainfall of 70 per cent, and Palakkad 57 per cent. "Normally, monsoon is characterised by its active and break cycles. One moment it will be intense and the next it would go cold, and then again it would revive and then die down, and so on it goes,” said Dr Manoj. But this time, there was no active-break cycles. “It was almost eternally active,” he said. “August is the month when the break periods are very long,” he added.

It had been nearly a century since the state had witnessed such devastation. Then, in 1924, the rainfall received for the season was 336.8 cm, the highest ever. It is not clear whether there were heavy rains during August in 1924. The detailed documentation of meteorological changes began only in the 1950s. The IMD official said that this year the total rainfall received was expected to touch at least 350 cm.

Wild monsoon a random phenomenon

Atmospheric scientist S Abhilash said that the stupendous monsoon surge was only a random occurrence. “During the past three decades, Kerala had witnessed more drought years or years with less than average monsoon than normal years,” said Abhilash who is researching on the state's drought years. Besides this year, there have been just two excess-monsoon periods in the past 30 years: 2007 and 2013. Both these years did not witness floods of this year's magnitude. Since 1980, he said the 'drought epochs' had been on the rise. There have been three drought epochs since 1980: 1982-88, 1999-2003, and 2008-2012. The three years since 2013 were also poor monsoon years, 2016 being the worst when both the south-west and north-east monsoons failed.

The August aberration, which has now led to an uncontrolled rise in water level, has been caused by another common phenomenon gone wild. “It is normal for a depression to form over the ocean but to have two in quick succession is strange,” said Dr Manoj. The depressions that have formed over the Bay of Bengal is so strong that it is pulling vapour laden winds from the opposite Arabian Sea side with tremendous force. These winds are blocked by the Western Ghats and rise quickly to form clouds, which is now coming down as heavy downpour over Kerala.

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