Landslide susceptibility and monsoon preparedness in Nepal: An engineering perspective

Just within about 20 days of June this year, 20 people died with 24 people missing, and 193 families affected by landslides and floods across the country. Landslides are major disasters in Nepal and now landslide dam outburst flood (LDOF) is also challenging. Every monsoon, we embrace a chain of slope failures. They often cause cascading effects such as landslide dam formation, the collapse of the dam, flash flood, and sediment washout and aggregation. For example, the Seti river flood killed more than 70 people in 2012 while the Kali Gandaki river buried 27 buildings in the Baseri landslide in 2015.

The recent Melamchi case on June 15, 2021, is also a landslide-dam outburst flood (LDOF) scenario. Such a case highlights the dire need for preparedness across Nepal. Though the precipitation extremity from the lens of hydrometeorology is not extraordinarily large in these particular weeks, a compound interaction with sediment hazards turns these landslides into a devastating disaster.