Kerala Rainfall Intensifies: Rising Casualties and the Science Behind Deadly Landslides
Context
Continuous heavy rainfall across Kerala has led to a rise in rain related fatalities, while thousands of residents have been shifted to relief camps due to floods, mudslides and landslides. The recent events have once again highlighted the high vulnerability of the Western Ghats, where prolonged rainfall followed by intense downpours creates ideal conditions for large-scale slope failures.
Key Highlights
- The India Meteorological Department (IMD) issued yellow alerts across all 14 districts of Kerala due to widespread rainfall activity.
- A separate landslide incident in Tirthahalli (Karnataka) claimed the lives of a migrant family, underscoring the regional impact of extreme rainfall.
- Landslides occur due to a combination of conditioning factors such as geology, slope characteristics and soil type, along with triggering factors like intense rainfall and human interference.
- According to ISRO’s National Remote Sensing Centre (NRSC) Landslide Atlas (1998 – 2022), the Western Ghats experience fewer landslides than the Himalayas but account for a disproportionately high number of fatalities.
- Activities such as quarrying, road construction, deforestation and plantation expansion have increased the ecological fragility of Kerala’s hill regions.
Key Concepts
Mechanism of Landslides
- Continuous rainfall saturates the soil, reducing its strength. Subsequent heavy rainfall weakens the bond between soil and rock, increases surface runoff and eventually triggers slope failure.
Why are the Western Ghats Highly Vulnerable?
- The region is characterised by steep slopes, intense orographic rainfall and lateritic soils, making it naturally prone to landslides.
- The Gadgil Committee and the Kasturirangan Committee have recommended enhanced protection of ecologically sensitive areas in the Western Ghats to minimise environmental degradation.
Kerala State Disaster Management Authority (KSDMA)
- The KSDMA is the nodal state agency responsible for disaster preparedness, mitigation and response under the Disaster Management Act, 2005.
Anthropogenic Factors
- Unplanned construction, indiscriminate excavation, quarrying and changes in land use disturb natural slopes and drainage systems, increasing the likelihood of landslides.
Way Forward
- Strictly implement regulations governing Eco-Sensitive Zones (ESZs) and regulate construction and quarrying activities in fragile hill regions.
- Improve real time weather forecasting (nowcasting) and strengthen landslide hazard zonation and early warning systems.
- Promote scientific land use planning and climate-resilient infrastructure in vulnerable areas.
- Integrate increasing incidents of extreme rainfall and cloudburst like events into long term climate adaptation and disaster risk reduction strategies.