Kerala’s Vulnerability to Landslides

Exceptionally heavy and widespread rainfall triggered fresh landslides, mudslides and flooding across Kerala, causing deaths and leaving several people missing. The event occurred two years after the devastating Wayanad landslides and renewed concern over the State’s growing landslide risk.

Why is Kerala Particularly Vulnerable?

• Western Ghats terrain: Kerala has steep and fragile slopes, especially across its central and northern districts.
• Intense monsoon rainfall: Heavy and prolonged rain rapidly saturates the soil and weakens slope stability.
• Cumulative rainfall: Landslides may result from rainfall accumulated over several days rather than from a single cloudburst.
• Geological conditions: Soil type, rock structure, geomorphology and slope angle make several areas naturally unstable.
• Dense drainage network: Water infiltration and surface runoff increase pressure within already weakened slopes.
• High human presence: Settlements, farms and infrastructure are located close to landslide-prone mountain slopes.

How Do Landslides Occur?

A landslide is the sudden downward movement of rock, soil, boulders or debris along a slope. Prolonged rainfall allows water to enter loose soil and the interface between soil and underlying rock, weakening their bond. A subsequent spell of intense rain increases runoff and water pressure, eventually causing slope failure.

Role of Weather Conditions

The rainfall was intensified by an offshore trough extending from north Gujarat to Kerala, strong southwesterly winds over the Arabian Sea and a north–south pressure gradient along India’s western coast. These conditions strengthened the monsoon flow and produced widespread rainfall over Kerala.

How Human Intervention Increases Risk

• Haphazard land use on fragile slopes
• Unscientific construction and road cutting
• Quarrying and excavation of hills
• Large-scale removal of forests and trees
• Expansion of plantations and settlements
• Disruption of natural drainage channels

Major Vulnerable Areas- Landslide risk is concentrated along the Western Ghats, particularly in districts such as Idukki, Pathanamthitta, Kottayam, Wayanad, Kozhikode and Malappuram.

Landslide Atlas

In 2023, ISRO’s National Remote Sensing Centre released a landslide atlas based on recorded events between 1998 and 2022. Although the Himalayan region recorded a larger number of landslides, Kerala accounted for a disproportionately high share of landslide-related fatalities.

Kerala needs stricter land-use regulation, scientific slope mapping, restrictions on quarrying and unplanned construction, restoration of natural drainage, improved early-warning systems and relocation of highly exposed settlements from vulnerable slopes.