In late June 2021, heavy rainfall caused a series of flash floods, landslides, and debris flows across Nepal, killing 18 people and leaving 21 more still missing according to media reports. Several people were forced from their homes in the Sindhupalchowk district as the Bhotekoshi river overflowed, and the Tatopani border point has remained closed since June 19 as the river flooded roadways in the Larcha and Kodari Bazaar areas. In Kanchanpur, the Mahakali river wiped out an under-construction bridge on June 19 as well, contributing to the ongoing loss of crucial infrastructure throughout the country. So far, the disasters have led to billions of dollars’ worth of losses to Nepal.

This image shows the Normalized Difference Vegetation Index (NDVI) for part of the upstream area of the Melamchi river in Nepal. NDVI highlights changes in vegetation in the area, and it shows both a new landslide in the lower part of the image in addition to changes in the sediment filling the river in the upstream part. The gray tones of the image are light tones where there is dense vegetation and dark where there is no vegetation. New landslides or eroded areas have no vegetation. Based on this image and local drone photography, it is likely that the section highlighted in the center shows eroded river deposits, while the northern-most area shows new deposition of sediment. The source of the new sediment remains unclear at this stage but is likely also associated with the flooding downstream in the village of Melamchi itself. This image was generated using PlanetScope imagery acquired on 06/21/2021. NDVI is masked using Unusable Data Masks provided with the imagery. Credits: Planet Team (2017). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA.

The NASA Earth Applied Sciences Disasters program area activated efforts to monitor the flooding and landslides in Nepal using Earth-observing data to assist in risk reduction, response, and recovery efforts. The program established a Core Team that met on June 23 to respond to imagery requests from the International Centre for Integrated Mountain Development (ICIMOD). Currently, the Disasters program is working to produce images of the area before and after the disaster.

The NASA ROSES A.37 research projects “Integrating SAR Data for Improved Resilience and Response to Weather-Related Disasters, Enabling Landslide Disaster Risk Reduction and Response throughout the disaster life cycle with a multi-scale toolbox Project,” and “Global Rapid Damage Mapping System with Spaceborne SAR Data Project” are providing support for the disaster response.