KOCHI: Three days of torrential rain that claimed 15 lives and unleashed landslips, flash floods and widespread destruction across Kerala also significantly narrowed the state’s monsoon deficit.
According to IMD data, Kerala recorded 232% excess rainfall during the three-day period from July 31 to August 2. Meteorologists attribute such extreme short-duration rainfall to the combined effects of global warming and El Niño.
According to IMD scientists, Kerala’s normal rainfall for the three-day period from July 31 to August 2 is 55.4 mm. This year, however, the state received 184.2 mm of rain during the period — 232% above normal.
Pathanamthitta bore the brunt of the rain fury, recording a staggering 533% excess rainfall in just 72 hours. Against the normal 40 mm for the period, the district received 253 mm of rain. According to official sources, Vadasserikkara recorded 331 mm of rainfall on the night of July 31, while nearby Laha received 236 mm.
Thiruvananthapuram registered a 457% rainfall surplus, followed by Kozhikode (326%), Kollam (302%) and Kottayam (300%). Among the heaviest single-day spells, Vagamon received 314 mm of rain on Friday night, Vadasserikkara 331 mm, Vazhikkadavu 308 mm and Ayyankunnu in Kannur 320 mm.
Kerala’s monsoon deficit has dropped from 36% on July 29 to 24% on August 3. However, the short spell of intense rainfall is unlikely to significantly replenish groundwater reserves, according to C P Priju, principal scientist at the Centre for Water Resources Development and Management (CWRDM).
“Recently we are witnessing extreme rainfall over a short duration of time in Kerala. This will not help to replenish the ground water resources as there will be heavy runoff and flash floods. Rainfall of normal intensity over a long duration will help infiltration and percolation of water, which is not happening in the case of intense rainfall.
State may receive intense rainfall from Aug 6 to 9
“Normally North Kerala receives more rain than South and Central Kerala. But the rain on July 31 and August 1 was more intense in South and Central Kerala,” he said.
Low-pressure systems may continue to bring heavy rain. But if sea surface temperatures rise beyond a certain level, the rain could become more intense and fall in short bursts, increasing the risk of flash floods, says a study by researchers P Vijayakumar and S Abhilash.
The rising intensity of rainfall increases the risk of landslides across the highland and midland slopes of the Western Ghats in eastern Kerala during the monsoon. Human interventions, particularly the large-scale conversion of hill slopes for cultivation, have further destabilised the terrain, making the region highly vulnerable to landslides of varying magnitudes.
“Heavy precipitation in a short duration brings runoff water beyond the capacity of the rivers and the sloping topography from high land of Western Ghats to low lying west coast accelerates the rush of floodwater,” the study said.
The IMD has issued Orange alert for 12 districts and yellow alert for Thiruvananthapuram and Kollam on Tuesday. There is possibility of intense rainfall from August 6 to 9, says the forecast.
CM Satheesan cites lack of timely alerts from IMD
T’Puram: Even as heavy rain and floods wreak havoc on state, the lack of timely and accurate weather forecasts in addition to the disaster response have come under scrutiny.
Chief Minister V D Satheesan on Monday said the IMD had not provided advance and timely alerts. He attributed the sudden flooding to extreme, localised rainfall.
“IMD could not predict the intensity of rain and could not give timely alerts. It was beyond their capacity due to the peculiar nature of the rainfall influenced by El Nino,” he said.
Kerala recorded 232% excess rain from July 31 to August 2
533% excess rainfall recorded in P’thitta in just 72 hours. The dist received
253 mm of rain against the normal 40mm for the period
Monsoon havoc
15 lives lost in rain-related incidents so far
7 people currently reported missing
316 relief camps opened across the state to shelter affected people
3,596 farmers impacted by heavy rain
165 hectares of agricultural land damaged
Orange alert issued
for all districts, barring T’Puram & Kollam, on Tuesday
Yellow alert in T’Puram & Kollam