Nepal Flash Floods (Geography)
Nepal Flash Floods (Geography)
Why In News:
On 26 August 2026, a series of devastating flash floods struck settlements along the Bhotekoshi River, the upper section of the Trishuli, sweeping through Bagmati Province, Nepal.
About the Event
Preliminary assessments suggest that an ice-rock avalanche may have entered and temporarily blocked the Lhende Khola .
The resulting accumulation and sudden release of water and debris produced a powerful downstream surge.
A seismic signal initially led to speculation about an earthquake, but subsequent assessments indicated that the signal could have been associated with glacial collapse rather than a conventional earthquake.
Bhotekoshi–Trishuli–Gandak River System
The Bhotekoshi forms part of the Trishuli–Narayani–Gandak river system, with its upper reaches linked to the Tibetan/Himalayan region and the Rasuwagadhi area of Nepal.
The Trishuli joins the Kali Gandaki at Devghat in Nepal to form the Narayani, which subsequently flows into India as the Gandak.
The Gandak is an important left-bank tributary of the Ganga, flowing through Nepal and India.
About Flash Flood
A flash flood is a sudden and rapid rise in water level, generally occurring within a short time after the triggering event.
It is particularly common in steep mountainous terrain, where steep slopes, narrow valleys and limited infiltration can produce rapid runoff.
Flash floods may be triggered by intense rainfall, cloudbursts, landslides, glacial/ice collapse, sudden breaching of natural dams or other abrupt releases of water.
Therefore, a flash flood does not necessarily mean a rainfall-induced flood.
Institutional Framework for Flash Floods
a) National Disaster Management Authority (NDMA)
The NDMA is India's apex statutory body for disaster management and is chaired by the Prime Minister.
It was established under the Disaster Management Act, 2005, which provides the institutional framework for disaster preparedness, mitigation, response and recovery.
b) National Disaster Response Force (NDRF)
The NDRF is India's specialised force for responding to natural and man-made disasters, including floods, cyclones, earthquakes and landslides.
It operates under the broader disaster-management framework created by the Disaster Management Act, 2005.
c) South Asia Flash Flood Guidance System
The South Asia Flash Flood Guidance System (FFGS) provides flash-flood forecasts and risk guidance for participating South Asian countries.
Its regional system is coordinated through the India Meteorological Department (IMD), New Delhi, supporting countries including India, Nepal, Bhutan, Bangladesh and Sri Lanka.