Heavy rainfall in Kerala: The progressive state's failure to learn from extreme weather events since 2018

The India Meteorological Department (IMD) also operates a weather station in the same area that recorded similar readings of heavy downpours at the same hour.

As per IMD's published definition, if 10 cm of rainfall is received at a station in one hour, the rain event can be termed a cloudburst.

However, for reasons yet to be made public, IMD has yet to confirm the CUSAT's declaration of the heavy rain in Kalamassery on May 28 as a cloudburst.

According to S Abhilash, associate professor with the CUSAT research centre, such intense showers for short durations are caused by towering cumulonimbus clouds, and normally, they occur as part of the summer rains, not the monsoon.

He said the atmospheric situation that prevailed on May 28 was not the onset of monsoons but that of high-intensity summer rains.

In the case of Kalamassey and all other areas of Kerala, the summer rains this year have been very late, and they created an impression of the early arrival of the southwest monsoon during the last fortnight of May.

There were frequent spells of high-intensity rains of short duration across central and southern Kerala, and they threw normal life out of gear in Kochi and the state capital, Thiruvananthapuram.

Areas south of Thrissur have yet to fully recover from the adverse impacts of the late summer rains, which lasted for over two weeks, although the monsoon officially set in on May 28.

Have cloudbursts occurred before in Kerala?

Since the 2018 deluge, Kerala has experienced extreme annual weather events. Climate experts pointed out possible cloudbursts as the reason for several landslides and flash floods in the hilly regions of the state, which have spread in Wayanad, Idukki, and Malappuram in recent years.

However, there was no scientific confirmation of the phenomenon using accurate measurements.

"Although there has been a drastic change in the nature and composition of rain in the last six years, the facilities to study are very few. Lack of accurate data also prevents the state from taking affirmative action. The whole state has just three or four rain gauge stations, and they are not working properly. The highly restricted and unexpected nature of cloudburst events makes the situation further murkier. Such events in smaller areas remain elusive for the existing rain stations," said Max Martin, a climate researcher at Sussex University in England.

According to Abhilash, heavy intermittent rains in the coming days of the west monsoon in the mountain regions would result in massive landslides and flash floods in rivers.

As a land of 44 rivers and a long, highly fragile Western Ghat stretch, Kerala has a lurking fear about the extreme weather events waiting to happen.

Above all, rains arrived in Kerala, known earlier for its salubrious climate, after an unusual and prolonged heat spell.

Even drinking water became scarce, and agricultural activities were heavily impacted. North-east monsoons are also traditionally strong here, and the two monsoons make it the God's Country together.

“Continuous, moderate-to-heavy rainfall is typically a feature of monsoons. However, instances of isolated and intense rains over a small area for short intervals are prevalent now. This kind of rain often causes great damage to those particular areas," says the Kerala State Council for Energy, Environment, and Water study.

According to Latha Cheriyan of the council, the concept of moderate rains is fading in Kerala, and each locality reports either excess rains or no rains.

M. G Manoj, a CUSAT Radar Research Centre scientist, said that cloudburst phenomena are increasing even in monsoon seasons. This occurs because of the extreme warming of the oceans, which enhances the formation of water vapour that concentrates at a particular spot as clouds.

He said this phenomenon is likely stronger this year as the monsoon was preceded by an exceptionally hot summer.

Experts pointed out that the Remal cyclone over the Bay of Bengal and the cyclonic formation off the coast of Tamil Nadu contributed significantly to the heavy rains that inundated Kerala last week.

These formations aggressively pulled the dense moisture-laden westerly winds toward the east. And the westerly that was sucked to the east dragged along with it to the Kerala coast, the rain-bearing clouds that were formed over the south Arabian Sea.

Though the intensity of the rains has lowered in the last two days, normal life remains at a standstill in south and central Kerala, while the northern region still lacks rains.

In the central and southern regions, the rains have flooded several low-lying areas, prompting the authorities to shift over 1500 families to relief camps.

The rain also inundated roads, bringing traffic to a grinding halt at many places. Thiruvananthapuram, Ernakulam, Alappuzha, Kottayam, and Thrissur districts were hit the worst.

In Thiruvananthapuram, water from the Killiyar River, Amayizhanjan Canal and other stormwater drains flooded streets and entered houses. Compounding these all, several city roads are now in disrepair under a slow-pedalling multi-crore smart city project.

Kochi, which had barely recovered from the cloudburst and the subsequent rains, saw large-scale waterlogging. Kalamassery, North Paravoor, Thrikkakara, Kakkanad, Edapally and MG Road bore the brunt of the rain.

North Paravoor and Kalamassery received 130mm of rainfall from 8:30 am to 5:30 pm on June 1, while Choondy received 90mm.

In Kochi, severe flooding of roads at Edappally, where NH 66 and NH 544 merge, led to tens of thousands of commuters stranded during the past few days amid incessant rains.

It has been pointed out that this could have been averted had the Edappally Canal been dredged during summer months and encroachers along the waterbody been removed in a time-bound manner as part of the ₹3,853-crore Integrated Urban Regeneration and Water Transport System (IURWTS) in the Greater Kochi area.

In November, the Kerala Infrastructure Investment Fund Board (KIIFB) increased the project's initial outlay from ₹1,528 crore to ₹1,728 crore.

Having identified that the region's reduced width and depth of canals due to rampant encroachments and garbage dumping was one of the major causes of intermittent flooding, Kochi Metro Rail Limited (KMRL) recommended widening major canals to a minimum width of 16.50 metres. It suggested building walkways with a minimum width of 2 metres on both sides of canals to activate the canal front and prevent further encroachments.

Meanwhile, an emergency meeting of the Kalamassery municipal council unanimously passed a resolution on June 1 asking the state government to identify and remove all encroachments shrinking the width and affecting the flow of waterbodies in the wake of unprecedented flooding during the current spell of downpours.

Congress-led UDF rules the municipality

Meanwhile, the opposition in the municipality, owing allegiance to the LDF, which rules Kerala, slammed the ruling UDF for its alleged failure to complete pre-monsoon works in a time-bound manner.

"This blame game is not specific to Kalamassery but happening across the state. Local bodies and the state government have permitted many illegal constructions blocking water flow. Kerala also has a dubious history of carelessly handling garbage, even during monsoons. Rivers, canals and drainages are now choking with solid wastes. They and large-scale changes in land use patterns in the hill areas are spelling doom for Kerala. The state has not learned any lessons from the recurring annual weather events. A poorly-equipped state is now remaining clueless on handling the impending danger," said Sreedhar Radhakrishnan, a Thiruvananthapuram-based conservation activist.

As for climatic factors, scientists agree that the magnitude and frequency of rain and flooding will increase with a warming climate worldwide. However, the characteristics of floods differ locally due to different geographic features and the severity of human factors like encroachments.