Dehradun, Aug. 27 -- The recent flash flood disaster in Nepal has once again raised concerns over the changing Himalayan climate and the growing risks posed by melting glaciers, shifting precipitation patterns and debris flows in the region.
Manish Mehta, a scientist at the Wadia Institute of Himalayan Geology who has studied disasters including those in Kedarnath, Rishiganga and Dharali in Uttarakhand, said developments in the Himalayas should not be viewed as isolated incidents.
Rising temperatures are causing several Himalayan glaciers to retreat, leaving behind large quantities of loose rocks, soil and debris. Unlike advancing glaciers that carry material along their path, retreating glaciers expose unstable debris that can be washed or swept downhill during intense rainfall or rapid snowmelt.
Mehta said scientists were also observing changes in precipitation at higher altitudes. Areas that traditionally received snowfall are increasingly witnessing rainfall, indicating that the snowfall zone is moving upwards while rainfall is reaching higher elevations.
When intense rain falls over a short period, loose debris can become saturated and suddenly move downhill, triggering landslides and debris flows. In some cases, snow and debris can temporarily block water channels, creating natural barriers. Their sudden collapse can send large volumes of water, rocks and soil rushing downstream.
Such flash floods are therefore often far more destructive than ordinary floods because they carry heavy debris capable of damaging buildings, roads and bridges.
Mehta said landslides and debris flows were natural features of the Himalayas, a young and geologically active mountain range. However, climate change could intensify the risks associated with these phenomena.
Published by HT Digital Content Services with permission from Millennium Post.