Why in News
- Torrential rainfall on the night of October 4–5, 2025 triggered over 110 major landslides in Darjeeling district and other parts of north Bengal.
- At least 32 dead, 40 injured, thousands stranded, with many missing.
- Areas like Mirik, Darjeeling, Kalimpong, Jalpaiguri, and Alipurduar were severely affected.
- The disaster coincided with Dashain festival, during which many families had gathered for celebrations, worsening human impact.
Relevance
- GS 1 – Geography: Landslide-prone Himalayan terrain, hydrology of Teesta and Balason rivers, impact of rainfall on soil stability.
- GS 3 – Disaster Management: Floods, landslides, NDRF operations, disaster preparedness and mitigation strategies.
- GS 3 – Environment & Climate Change: Extreme rainfall, climate change impact, hydropower projects and river management.
Basic Overview
- Rainfall: ~261 mm in 12 hours caused soil instability, river overflow, and landslides.
- Geography: Darjeeling and Mirik are hilly regions cradled between Western Himalayan ranges and alpine forests.
- Infrastructure Damage: Roads vanished under mud; Balason river iron bridge collapsed, temporarily cutting off connectivity.
- Tourism Impact: Mirik and surrounding areas rely heavily on tourism, now disrupted, affecting livelihoods.
Human Tragedy & Social Impact
- Personal accounts reveal loss of children and relatives due to sudden landslides during sleep.
- Many families lost entire households, highlighting vulnerability during extreme weather.
- Psychological trauma and grief compounded by the festival season, which is usually associated with celebration.
- Community displacement: Families moved to temporary shelters like Dudhia community hall.
Geological & Environmental Factors
- Terrain: Steep slopes, unstable soil, and heavy rainfall combine to create high landslide risk in Darjeeling hills.
- Hydropower Projects: Tala hydropower dam and other projects contributed to flooding after dam gates failed to open.
- River Systems: Teesta and Balason rivers played a role in rapid water flow, contributing to soil erosion and infrastructure collapse.
- Climate Dimension: Increased frequency of extreme rainfall events linked to climate change may exacerbate such disasters.
Economic & Livelihood Impact
- Tourism-dependent communities lost income due to road closures and suspended travel to hill destinations like Mirik and Sandakphu.
- Infrastructure damage disrupted local trade and access to essential services.
- Additional costs for restoration, temporary shelters, and compensation added to government expenditure.
Humanitarian & Social Implications
- Highlighted vulnerability of hilly populations to flash floods and landslides.
- Exposed the need for early warning systems, flood forecasting, and community awareness.
- Emphasized importance of resilient infrastructure in disaster-prone regions.
- Psychological impact on children, families, and displaced populations.
Broader Implications
- Governance: Need for proactive disaster management and coordination between central, state, and local bodies.
- Environment & Climate Policy: Importance of sustainable land use, forest cover maintenance, and hydropower regulation.
- Disaster Preparedness: Integration of early warning systems, evacuation plans, and local community training.
- Socio-Economic Resilience: Strengthening tourism, agriculture, and infrastructure to withstand natural disasters.
Landslide Basics
Definition & Types
- Landslide: Downward and outward movement of rock, soil, or debris on slopes due to gravity.
- Types of Landslides:
- Rockfalls: Sudden free-fall of rocks from steep cliffs.
- Debris Flows: Rapid movement of loose soil, rocks, and water.
- Slumps: Rotational sliding of soil along a curved surface.
- Creeps: Very slow downward movement of soil or rock.
- Complex Landslides: Combination of types (e.g., slump followed by debris flow).
Causes of Landslides
A. Natural Causes
- Heavy rainfall / Snowmelt: Saturates soil, reduces cohesion.
- Earthquakes: Trigger slope failure in hilly regions.
- Volcanic activity: Lava and ash destabilize slopes.
- Steep slopes and unstable geology: Common in Himalayas, Western Ghats.
B. Anthropogenic / Human-Induced Causes
- Deforestation: Removes root structures stabilizing slopes.
- Construction & urbanization: Roads, buildings, and terrace cuts destabilize slopes.
- Mining / Hydropower projects: Excavation weakens natural slope stability.
- Poor drainage & irrigation: Waterlogging increases pore pressure in soil.
Regions Prone to Landslides in India
- Himalayas: Uttarakhand, Himachal Pradesh, Darjeeling, Sikkim.
- North-Eastern Hills: Arunachal Pradesh, Meghalaya.
- Western Ghats: Kerala, Karnataka, Maharashtra.
- Other Regions: Nilgiris (Tamil Nadu), parts of Andaman & Nicobar Islands.
