Preparing 3D terrainLoading elevation geometry…
Elevation(m)
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Selected record

Viewer controls

3D · Left drag
Orbit around the terrain.
2D · Drag
Pan the north-up GIS map.
Wheel
Zoom in or out.
3D · Right drag
Pan the terrain view.
3D / 2D
Change renderer without changing visible layers or the selected record.
Click route
Inspect coordinates, elevation and the cross-valley profile.
Click marker
Open a compact source or bridge record; select Read more for complete details.
Click impact
Open a compact assessed record or grouped-record summary; select Read more for complete details.
Layers
Show or hide marker categories and locate individual records from their layer lists.
Guided journey
Follow the reconstructed flood pathway through the 3D valley, with optional pauses at enabled evidence records.
Distance
Select any two DEM locations to compare horizontal, straight-line 3D, and terrain-surface distance.
Elevation profile
Select any two DEM locations to plot elevation along the straight A–B transect.
Impact colours
Muted violet rings mark destroyed assets, ochre rings mark damaged assets, and slate count badges group nearby records at the current scale.
Measure
Select two route locations to calculate along-path distance and elevation change.
N · E · Z
Camera-relative north, east and elevation orientation in 3D.

Research information

About this Project

With respect and solidarity

We extend our deepest sympathy to the people and communities affected by the 26 August 2026 disaster, especially to those who lost family members and loved ones, sustained injuries, were displaced, or suffered the loss of homes, livelihoods, infrastructure, and cultural or natural heritage. We stand in solidarity with Nepal and with every community along the affected region.

This research is offered in the hope that it can strengthen scientific understanding, risk awareness, preparedness, and future efforts to prevent or mitigate such hazards and catastrophes.

Project and credits

Research and application
Niki Evelpidou1, Alexandros Liaskos1, Evaggelos Spyrou1, and Nitesh Khadka2
Affiliations
1 Department of Geology and Geoenvironment, National and Kapodistrian University of Athens
2 Centre for Water Resources Studies, Institute of Engineering, Tribhuvan University, Nepal
Contact
evelpidou@geol.uoa.gralexliaskos@geol.uoa.grevspyrou@geol.uoa.grniteshkhadka48@gmail.com
Terrain data
NASA High Mountain Asia DEM and Copernicus DEM
Event and impact evidence
USGS, GFZ, United Nations Satellite Centre (UNOSAT), Copernicus Emergency Management Service (CEMS), Humanitarian OpenStreetMap Team (HOT), Sentinel Asia, JAXA, Institute of Water Modelling (IWM), and Taiwan Space Agency (TASA)
Mapping and software
OpenStreetMap contributors, OpenFreeMap, CARTO, NASA GIBS, OpenTopoMap, Three.js, OpenLayers, and Leaflet

How to cite

Evelpidou, N., Liaskos, A., Spyrou, E., & Khadka, N. (2026). 2026 Nepal Debris Avalanche and Flash Flood: Interactive 2D and 3D terrain reconstruction [Web application]. National and Kapodistrian University of Athens. https://nkua.cloud/Nepal-Flood-2026/

Licence and reuse

Except where third-party data, basemaps, imagery, logos, or source materials are separately credited, the original text, interface, visualisation design, and research outputs of this application are licensed under the Creative Commons Attribution 4.0 International licence (CC BY 4.0).

You may share and adapt this material provided that you give appropriate credit, link to the licence, and indicate whether changes were made. Third-party materials remain subject to their respective terms and licences.

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