Glacier bursts-triggered debris flow and flash flood in Rishi and Dhauli Ganga valleys: A study on its causes and consequences

Abstract

The territory of the Uttarakhand Himalaya is highly susceptible to meteorological and geophysical hazards. Earthquakes, cloudburst-triggered landslides, debris flows, and flash floods are very common, frequent, intensive, and devastating. Snow avalanches/glacier outbursts are rare, however, they are very dangerous. This article examines the Rishi and Dhauli Ganga tragedy that occurred due to glacier outbursts on February 7, 2021 in the source area of Rishi Ganga, i.e., ‘the Nanda Devi glacier’ in Chamoli district, Uttarakhand. It describes the major drivers, which triggered debris flows/flash floods in the Rishi and Dhauli Ganga valleys, and illustrates its consequences. The calamity has led to the loss of approximately Rs. 20,000 million and the death of about 205 people. Land degradation, loss of soils and forests, and formation of landslide scars in the affected areas were other consequences. This study suggests several policy measures to reduce the casualties related to natural hazard processes.