What triggered torrential rain in Kerala

Failure to address underlying ecological issues leading to floods, says CUSAT expert

The western areas of Kochi, now under a lockdown to contain Covid19. is flooded with overnight rains.

The gradual transition in the strength of the wind from 14 km/hour on August 1 to 85 km/hr on August 6 has triggered heavy rainfall over the west coast of the country and it is likely to last for two to three days, according to observations by scientists at the Advanced Centre for Atmospheric Radar Research (ACARR) in the Cochin University of Science and Technology.

“In conjunction with the recent development of depressions over the Bay of Bengal, radar observations taken at the ACARR show that the strength of the wind at lower troposphere (below 2 km in the atmosphere) observed from radar on August 1 was around 14 km/hour, which gradually picked up momentum and it reached about 85 km/hour on August 6,” Ajil Kottayil, scientist at ACARR, said on Friday.

Wind a trigger

This kind of transition in the wind triggers heavy rainfall over the west coast of India. A heavy rainfall thus triggered could last two to three days, he said.

Stating that extreme heavy rainfall events during monsoon season were not an abrupt phenomena, Dr. Ajil said certain priming occur prior to their manifestation. “They evolve following an intensification of low-pressure system over central India. The transition in monsoon circulation from normal to heavy rainfall is in fact gradual, which actually facilitates their predictability. The wind observations taken at the ACARR can ideally capture the signals of heavy rainfall a few days prior to their actual incidence,” he said.

Kerala situation

On why Kerala was facing the continued threat of successive floods, Dr. Ajil said “it would be because we have failed to address the underlying ecological issues promoting water stagnation. Extreme weather events cannot be prevented any time in future but equipping ourselves to a changed world is the only sustainable solution”, he said.

The scientist said the past two years, though bitter, was but a novel experience for the State already ensnared in unscientific planning, illegal encroachments, and paralleled with a dense population.