Eight years on from the deadly 2018 floods, Kerala has been deluged again. This time, experts Down To Earth spoke to say the mathematics of floods in the state has changed drastically.
Kerala has made significant progress in disaster response since the catastrophic floods of 2018. Early warning systems have improved, rescue agencies are better coordinated, and communities have become more aware of flood risks.
Yet every successive monsoon demonstrates that disaster response alone cannot compensate for decades of ecological degradation and unsustainable land use.
Deluged again
Over the past four days, torrential rain has battered almost the entire state, from the northern districts bordering Karnataka to the below-sea-level polders of Kuttanad.
Rivers burst their banks, landslides tore through the fragile slopes of the Western Ghats, highways disappeared under floodwaters. Homes collapsed, roads and bridges were washed away, electricity networks were disrupted, and agriculture suffered another devastating blow.
The most dramatic scenes unfolded along the Western Ghats stretches which pass through the eastern edges of the state. Within just twelve hours, multiple landslides struck the high ranges of Idukki, Pathanamthitta and Kottayam. Idukki alone recorded scores of landslips within a day. Rivers including the Periyar, Bharathapuzha, Chaliyar, Chalakudy, Pamba, Manimala, Meenachil and Achankovil rose simultaneously, flooding settlements across central and northern Kerala. As water rushed down the mountains, it spread into the floodplains of Alappuzha and Kuttanad, where communities once again braced for prolonged inundation.
A total of 28 people have died so far due to floods in Kerala as of August 5, 2026. Four are missing. Around 418 relief camps are providing shelter to 18,434 affected people. All districts except Kollam and Thiruvananthapuram in the far south are affected.
Kerala received 13.9 cm of rainfall between July 31 and August 2 against a normal of just 4 cm, more than three times the seasonal average for the period.
Some of the rainfall resembled cloudburst conditions. A rain gauge at Vadasserikkara in Pathanamthitta recorded 361 mm of rainfall in twenty-four hours. Anakkampoyil on the Kozhikode-Wayanad border received 340 mm within about thirty-five hours, while Laha in Pathanamthitta recorded around 250 mm in a day. Meppadi in Wayanad, still recovering from the recent tunnel landslide tragedy, was again lashed by exceptionally heavy rain.
Yet what unfolded across the state was not simply another episode of heavy rain. It was another reminder that Kerala’s flood disasters are becoming progressively more complex and increasingly shaped by human decisions as much as by meteorology.
Ironically, the floods this year have happened after much of Kerala’s high ranges had experienced a deficient monsoon. Until the end of July, districts such as Idukki and Wayanad had recorded rainfall deficits exceeding fifty per cent. Then, within a day, parts of Idukki received around 11 cm of rain, sharply narrowing the seasonal deficit. This paradox lies at the heart of Kerala’s changing monsoon.
“The state is not necessarily receiving more rain than it did decades ago. Long-term rainfall records indicate that Kerala’s annual rainfall has remained broadly stable and has even declined marginally over the past century. What has changed is how the rain falls. Instead of arriving steadily over four months, the monsoon is increasingly delivering large volumes of rain within a few hours or days,” points out S Abhilash, director of Advanced Centre for Atmospheric Radar Research at Cochin University of Science and Research (CUSAT).
The story begins much higher up, in the forests and mountains of the Western Ghats. These mountains once functioned as one of peninsular India’s most effective natural water regulation systems. Dense forests, deep soils and thick vegetation absorbed monsoon rainfall and released it gradually into streams over days and weeks.
That natural sponge has steadily weakened. Roads have sliced through fragile hill slopes. Hills have been cut for construction. Quarries have proliferated across the high ranges. Forests have fragmented. Natural drainage channels have been blocked or altered. Agricultural expansion has destabilised steep slopes. Every one of these interventions has reduced the ability of the landscape to hold water. Instead of infiltrating the soil, rainwater now races downhill almost immediately.
Renowned geologist C P Rajendran warns that nearly 10,000 square kilometres of Kerala fall within landslide-prone terrain. Much of this lies along the ecologically fragile Western Ghats, where steep slopes become highly unstable after prolonged or intense rainfall. The danger increases dramatically when slopes are cut without proper retaining structures, natural drainage is obstructed, or construction disturbs the stability of the terrain.
The state’s own expert committees have reached similar conclusions. Following major landslides in Wayanad, the Kerala Legislative Assembly’s Environment Committee studied recurring slope failures across the state and recommended stronger regulation of construction in the high ranges, scientific land-use planning, improved monitoring of vulnerable slopes and better coordination among departments responsible for forests, geology, revenue and disaster management. Many of these recommendations remain only partially implemented.
The consequences are becoming increasingly visible. Landslides that were once regarded as isolated disasters are now occurring with alarming regularity across multiple districts during every intense spell of monsoon rain. The question confronting Kerala is therefore no longer whether climate change is real. It is whether the state has made itself far more vulnerable to a changing climate by steadily weakening the natural systems that once protected it. The transformation is not confined to the mountains.
Kerala has also dismantled many of the natural systems that once moderated floods downstream. Paddy fields, wetlands and floodplains are often viewed merely as agricultural or ecological assets. In reality, they are among the state’s most effective flood-control infrastructure. During heavy rain, they temporarily store enormous volumes of water before releasing it gradually into rivers.
Over the past five decades, Kerala has lost nearly three-fourths of its paddy fields. From around 876,000 hectares in the mid-1970s, the area under paddy cultivation has shrunk to barely 200,000 hectares. Wetlands have suffered a similar fate. Reclamation for housing, roads, industries and commercial development has steadily reduced the capacity of landscapes such as the Vembanad wetland system to absorb floodwaters.
“The mathematics of flooding has therefore changed fundamentally. Even if annual rainfall remains broadly similar, there are now far fewer places left to store rainwater. As a result, much larger volumes of water reach rivers simultaneously, producing sharper flood peaks and more destructive inundation. Urbanisation has made the problem worse,” points out Kochi-based researcher C Jayaraman.
A few decades ago, rain falling on a household compound largely soaked into the ground. Today, it lands on concrete roofs, paved courtyards, asphalt roads and interlocking tiles before flowing directly into drains. Across Kerala’s expanding towns and cities, streams have been covered, canals narrowed, stormwater drains clogged and natural drainage channels erased by unplanned construction. Urban flooding has consequently emerged as one of the state’s fastest-growing environmental risks. Cities such as Kochi, Thiruvananthapuram and Kozhikode no longer require overflowing rivers to flood. A few hours of exceptionally heavy rain are often enough to paralyse traffic, inundate homes and disrupt public services. The problem extends beyond the cities.
Kerala’s rivers are among the shortest in India. Most originate in the Western Ghats and travel barely 80 to 100 kilometres before reaching the Arabian Sea. Their steep gradients make them naturally fast-flowing. Heavy rainfall in the hills can therefore reach downstream settlements within hours. But water can reduce flood risk only if it can move freely. Many river mouths have gradually become shallower because of sediment deposition. Canals have lost carrying capacity after years of neglect and inadequate desilting. Important drainage structures, including the Thottappally Spillway that helps regulate floodwaters in the Kuttanad region, no longer operate at their optimum hydraulic efficiency. Water that rushes rapidly from the mountains is therefore slowed before it reaches the sea, prolonging flooding across central Kerala.
Kerala’s challenge, therefore, is not simply to build higher embankments or larger drains. It is to restore the landscapes that once moderated floods naturally. Protecting forests in the Western Ghats, conserving wetlands, preventing further loss of paddy fields, regulating construction on unstable slopes, restoring streams and canals, improving reservoir operations and maintaining drainage infrastructure are no longer isolated environmental concerns. Together, they form the state’s most effective flood defence.