Data sources
- Planet PlanetScope, 26 August 2026, approximately 3 m ground sampling distance — post-event optical imagery.
- Copernicus Sentinel-2, 27 August 2026, 10 m ground sampling distance — post-event optical imagery.
- OpenStreetMap building footprints and road network, extracted for the area of interest.
- Google Open Buildings footprints, as a complementary settlement dataset.
- Local units of the affected districts, Department of Survey, Nepal — municipality and rural municipality boundaries, shown as the labelled administrative outlines.
- Settlements and villages, Department of Survey, Nepal — named settlement points, each carrying its local unit, district and province.
Method
The potential affected zone was delineated through visual interpretation of the post-event Planet and Sentinel-2 scenes, mapping observable channel change, sediment deposition and inundation along the river corridor. The observation zone denotes the wider area reviewed during interpretation, and is shown for context rather than as an assessed extent.
Estimated affected buildings were derived by intersecting building footprints with the delineated zone. The headline layer combines the OpenStreetMap and Google Open Buildings sets and deduplicates them against one another, so it holds fewer buildings than the two single-source layers do in total. Each single-source layer is also published separately, so the contribution of either dataset can be inspected on its own. These are modelled estimates of exposure, not counts of confirmed damage.
Limitations
This is a rapid, preliminary assessment produced for situational awareness and to support early prioritisation of response. It has not been verified on the ground. Optical imagery is constrained by cloud cover, terrain shadow and sensor resolution, and features smaller than the ground sampling distance cannot be resolved. Building footprint datasets differ in vintage, completeness and positional accuracy between areas, so counts derived from them are indicative rather than exact. All figures and extents are provisional and subject to revision as further information becomes available.
Planned refinement
A more detailed and accurate damage and exposure assessment will be undertaken once high-resolution imagery has been acquired for the affected area. The layers presented here will be superseded by that analysis.
Boundaries and designations
The designations employed and the presentation of material on this map do not imply the expression of any opinion whatsoever on the part of the Asian Disaster Preparedness Center concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Administrative boundaries, place names and basemap content are supplied by third parties and are shown for reference only.
The analysis is confined to physical change observable in the imagery within the area of interest. It makes no determination as to the origin, cause or attribution of the event, and nothing in this product should be construed as an assessment of conditions beyond the mapped extent.
Prepared by the Asian Disaster Preparedness Center (ADPC). Provided “as is”, without warranty of any kind. ADPC accepts no liability for any use of, or reliance placed on, this product or the data it presents.
