Natural to Human-Amplified Hazards: Escalating Landslides and Cascading Floods in Uttarakhand, Northwest Himalaya

Abstract

Uttarakhand, located in the tectonically active northwest Himalaya, is one of the most landslide-prone regions of India due to its fragile geology, steep topography, active tectonics, and intense monsoonal rainfall. While landslides have historically been a natural hazard in the region, recent years have witnessed a marked escalation in their frequency, spatial extent, and cascading impacts, particularly in the form of flash floods and debris flows. This study presents a comprehensive synthesis of landslide activity during 2020–2025, based on multi-source datasets compiled from the Indian Space Research Organisation (ISRO), the Geological Survey of India (GSI), peer-reviewed literature, and official reports.

The analysis reveals a sharp increase in documented landslides from fewer than 400 events per year during 2020–2021 to more than 1,800 events in 2024, with elevated activity persisting into 2025. Spatial clustering of landslides is prominently observed in Rudraprayag, Chamoli, Uttarkashi, and Tehri Garhwal districts, particularly along major infrastructure corridors associated with the Char Dham all-weather road project, hydropower development, and urban expansion. The results indicate that anthropogenic disturbances—such as unscientific slope cutting, extensive blasting, deforestation, road widening, and improper muck disposal—have significantly amplified natural triggers, including extreme rainfall and local seismicity. These human-induced modifications have reduced slope stability thresholds, converting episodic, rainfall-driven landslides into recurrent, high-impact, human-amplified hazards.

Although the broader escalation of landslide risk in Uttarakhand has evolved over the last decade, the present study demonstrates that the most pronounced intensification has occurred during the 2020–2025 period, coinciding with accelerated infrastructure development. The findings highlight the urgent need for geology-driven land-use planning, environmentally sensitive engineering practices, and integrated multi-hazard risk assessment frameworks to mitigate future disasters in the fragile Himalayan terrain.