In late September and early October this year, unusually heavy monsoon rains led to deadly flooding and landslides in Nepal’s southern Kathmandu region. The disaster comes just over three years after a similar catastrophic event in the country’s Melamchi Valley, when devastating floods sent rocks, trees and mudflows sweeping through the valley, displacing thousands and wreaking havoc on local communities.
Using sophisticated technology, researchers have now evaluated the June 2021 Melamchi flood’s impact with remarkable precision and developed insights that could help predict — and perhaps prevent — future catastrophic floods.
Led by Josh West, professor of Earth sciences and environmental studies, and PhD student Chan-Mao Chen, both at the USC Dornsife College of Letters, Arts and Sciences, the study, published in Nature Geoscience, provides a detailed analysis of the flood’s triggers by combining cutting-edge satellite imagery, digital models of the valley’s landscape and field data. This approach allowed the researchers to investigate how rainfall, snowmelt and steep terrain worked together to unleash the powerful flood.