Wayanad landslides: What makes Kerala so vulnerable to such disasters?

Landslides in Kerala’s Wayanad district have killed over 140 people and injured dozens of others. The disaster triggered by torrential rains struck the hilly areas near Meppadi in Wayanad on Tuesday morning (July 30).

Several landslides were reported in Mundakkai and Chooralmala villages under Meppadi Panchayat. Multiple bodies were recovered from the Chaliyar River in Malappuram’s Nilambur region, while many others are feared to have washed away, reported Indian Express.

Rescue efforts were obstructed after the main bridge leading to Mundakkai village collapsed. The Indian Army and Navy teams, along with the National Disaster Response Force (NDRF), are being deployed to assist in rescue operations.

Almost every year Kerala witnesses deadly landslides in the monsoon season. But why does this happen? We explain.

Recent floods, landslides in Kerala

Kerala reported devastating floods in 2018 – the worst in its history – that killed 483 people. In just three days in August of that year, the southern state received a third of its average annual rainfall.

As many as 295 people died due to landslides in Kerala between 1961 and 2016, Dr S Sreekumar, disaster risk consultant, told The Week in 2022. “There is a massive increase in death and damage rate as well as instances of landslides since 2018,” he said.

Similar tragedies were reported in the monsoon of 2019 and 2020 that claimed over 100 lives.

In 2021, dozens of people died due to multiple landslides and floods in the districts of Kottayam and Idukki in Kerala.

Several people died in the state due to rain-related incidents such as landslips and flash floods in 2022.

The Climate Report of India released by the India Meteorological Department (IMD) last January found that extreme weather events claimed 32 lives in Kerala in 2022. While 30 died due to flooding and heavy rainfall, two others were killed in thunderstorms and lightning, reported Times of India.

In July 2022, the Ministry of Earth Sciences told the Lok Sabha that Kerala witnessed the most number of major landslides in the country in the past seven years. Of the 3,782 landslides between 2015 and 2022, about 59.2 per cent, or 2,239, were reported in God’s Own Country.

Landslides in Kerala

Kerala is prone to heavy rains and flooding, with an estimated 14.5 per cent of land area seen as vulnerable.

According to experts, 13 districts in Kerala are susceptible to landslides except the coastal district of Alappuzha, as per The Week report.

The Kerala State Disaster Management Authority (KSDMA) has identified 1,848 square kilometres, 4.75 per cent of the state’s total area, as High Landslide Hazard Zone.

About 8 per cent of the area in the Western Ghats in the southern state is labelled as a critical zone for mass movements, including debris flow, landslides, rock falls and slumps, reported The Week.

A recent AI-aided study revealed that about 13 per cent of Kerala is extremely prone to landslides, with Idukki, Palakkad, Malappuram, Pathanamthitta and Wayanad categorised as highly vulnerable regions.

The research by Kerala University of Fisheries and Ocean Sciences (Kufos) found a 3.46 per cent increase in the extreme landslide susceptibility zone in the southern state after the 2018 “extreme rainfall event”, reported The New Indian Express (TNIE).

In 2011, the Western Ghats Ecology Experts Panel (WGEEP), chaired by ecologist Madhav Gadgil, had classified most of the Idukki and Wayanad districts as category 1 under eco-sensitive zones, meaning they were highly vulnerable and forest land in these areas should not to be used for agriculture or non-forest activities. However, two years later, the Kasturirangan report had toned down the recommendations, reported Scroll.

ALSO READ: Wayanad landslides kill over 50: Why do landslips occur more frequently during the rains?

Reasons for landslides

Climate change, deforestation are some factors blamed for Kerala’s frequent landslides in the rainy season.

The changing rainfall pattern in Kerala over the last few years has contributed to the issue. The state has seen a delay in the monsoon rains. TV Sajeev, a scientist at the Kerala Forest Research Institute, told Scroll in 2020, “When I was in school, the day school used to reopen was the day the rains arrived – June 1. Now, it has been pushed to the first or second week of June. Then you have intermittent rains, not continuous. At the end of July until mid-August, there is high intensity rainfall.”

Speaking to Frontline magazine, S Abhilash, Research Director at Advanced Centre for Atmospheric Radar Research in Cochin University of Science and Technology, said, “There is not much variation in the total rainfall data over the season, but rainfall is concentrated over a fewer number of days. Spells of heavy rain, which lead to calamities like floods and landslides, are a result of climate change induced by global warming.”

Post disaster investigations have found unprecedented heavy rains were responsible for landslides.

Construction activities in vulnerable areas also lead to disasters. “A lot of construction activities are happening in our state [Kerala] in vulnerable areas. We built more roads and culverts. However, even now our engineering structures are being built based on the amount of rainfall and intensity of rainfall in older days. There is a need to rethink new or added risk factors while constructing roads or culverts. We are not providing room for the river in many places and this is an important factor for flash floods. Our unscientific construction mechanisms are major causes for the destruction we are facing,” Sreekumar told The Week.

According to Girish Gopinath, head of the Kufos Department of climate variability and aquatic ecosystems, “Human activities in the periphery of Wayand and Idukki high ranges are a major factor contributing to landslides," TNIE reported.

As BOOM noted, landslides are caused by the additive impact of water on topography, geology, soil and vegetation. G Sankar, a former scientist with the National Centre for Earth Science Studies (NCESS), explained that the Western Ghats in Kerala are marked by thick soil cover but human interventions over the years have affected them.

“During monsoon, the overburden soil gets saturated due to percolating rainwater, making it unstable. When the water content reaches a threshold level, the soil mass becomes weak triggering debris flows,” he told BOOM in 2021.

“There are small drainage channels present on the surface of the hilly areas. Erecting buildings and contour bunds block their natural flow. During the rains, the water that percolates get concentrated leading to increased pore pressure along the channel,” Sankar said.

“All mountain drainage channels should be free helping easy runoff. We should not construct buildings on or near these channels or at least give leverage of 50m on both sides,” he added.

It is the marginalised who are bearing the brunt of the natural calamities.

The landslides and floods in Kerala affect historically marginalised and vulnerable groups, such as women, the elderly, children, persons with disabilities, Scheduled Tribes, Scheduled Castes and fisherfolk, the most, according to The Rebuild Kerala Development Programme paper.

With inputs from agencies