Post-event optical stereo DEMs (WorldView-2, WorldView Legion 2/3, WorldView-3) for the 2026-08-26 Rasuwa (Langtang Lirung) ice-rock avalanche, Nepal
Abstract
This record provides digital elevation models (DEMs) from post-event optical stereo satellite images following the 2026-08-26 ice-rock avalanche on the north flank of Langtang Lirung, Rasuwa District, Nepal. The DEMs were produced from Vantor WorldView-2, WorldView-3 and WorldView Legion 2/3 stereo images acquired 2026-08-27 through 2026-09-08. The record includes pair DEMs (WorldView-2, WorldView Legion 2/3), multi-view DEM composites for WorldView-2 and WorldView-3, a post-event composite of all sources, and two elevation-change maps. All products are cloud-optimized GeoTIFFs in EPSG:32645 (WGS 84 / UTM zone 45N) with heights above the WGS 84 ellipsoid, posted at 2 m. The DEMs are co-registered to a common pre-event reference surface; users may wish to perform their own co-registration for their application. License: CC BY-NC 4.0. Original Level-1B Imagery (c) 2026 Vantor. 1. Products File suffixes: _dem single pair DEM; _ordered priority-ordered composite; _wmean weighted-mean composite; _hs hillshade; _ordered_source input that supplies each pixel of the ordered composite (listed in _ordered_source_index.csv); _count number of inputs per pixel. Nodata is -9999 in elevation, elevation-change and count layers and 0 in hillshade and source layers. 00_*_preview.png files are quick-look figures. 1.1 Input images Eleven Vantor Level-1B images. Satellite azimuth is from the target to the satellite. Geometry for the WorldView-2 and WorldView Legion 2 images is from the image metadata; for the others, view angles are from the Vantor catalog and sun angles are computed from the acquisition time. catalog ID sensor acquired (UTC) off-nadir (°) satellite azimuth (°) satellite elevation (°) sun azimuth (°) sun elevation (°) B030001100EF4C10 WorldView-2 2026-09-08 04:59:51 15.5 17.8 72.8 137.7 61.3 B030001100EF4E10 WorldView-2 2026-09-08 05:00:40 9.1 184.8 79.6 138.1 61.4 B030001100EF4F10 WorldView-2 2026-09-08 04:59:40 19.9 16.9 67.8 137.7 61.2 B12000110123B110 WorldView Legion 2 2026-09-06 05:23:18 30.2 343.6 57.4 147.4 65.0 B12000110123B310 WorldView Legion 2 2026-09-06 05:23:46 17.0 305.5 71.7 147.7 65.0 B1300011011E5610 WorldView Legion 3 2026-09-07 01:43:31 13.4 7.2 75.6 94.9 22.0 B1300011011E5810 WorldView Legion 3 2026-09-07 01:44:02 18.7 91.6 70.0 95.0 22.1 B040001100881410 WorldView-3 2026-08-27 05:04:50 21.9 14.4 65.9 132.1 64.6 B040001100881610 WorldView-3 2026-08-27 05:05:11 9.2 17.2 79.9 132.2 64.7 B040001100882F10 WorldView-3 2026-08-27 05:05:34 12.8 219.8 75.9 132.4 64.8 B040001100881710 WorldView-3 2026-08-27 05:06:11 26.4 190.3 60.8 132.6 64.9 1.2 Pair DEMs (rasuwa_post_vantor_pairs.zip) file sensor convergence angle (°) time between images (s) rasuwa_post_wv02_20260908_B030001100EF4C10-B030001100EF4E10_2m_dem_v1.0.tif WorldView-2 27.4 50 rasuwa_post_wv02_20260908_B030001100EF4C10-B030001100EF4F10_2m_dem_v1.0.tif WorldView-2 5.1 11 rasuwa_post_wv02_20260908_B030001100EF4E10-B030001100EF4F10_2m_dem_v1.0.tif WorldView-2 32.5 60 rasuwa_post_lg02_20260906_B12000110123B110-B12000110123B310_2m_dem_v1.0.tif WorldView Legion 2 21.1 28 rasuwa_post_lg03_20260907_B1300011011E5610-B1300011011E5810_2m_dem_v1.0.tif WorldView Legion 3 23.3 30 1.3 Composites (rasuwa_post_vantor_composites.zip) file inputs rasuwa_post_wv02_20260908_B030001100EF4C10-B030001100EF4E10-B030001100EF4F10_2m_{ordered,wmean}_v1.0.tif the three WorldView-2 pairs rasuwa_post_wv03_20260827_B040001100881410-B040001100881610-B040001100882F10-B040001100881710_2m_{median,count,nmad}_v1.0.tif median of the six WorldView-3 pairs below, with the per-pixel pair count and NMAD (2 or more pairs) rasuwa_post_vantor_20260827-20260908_2m_{ordered,wmean}_v1.0.tif all sources (WorldView-2 > Legion 2 > Legion 3 > WorldView-3); recommended The WorldView-3 median combines six cross-track pairs of the four 2026-08-27 images: pair convergence angle (°) B040001100881610-B040001100881410 13.9 B040001100881610-B040001100882F10 16.9 B040001100882F10-B040001100881710 22.4 B040001100882F10-B040001100881410 30.8 B040001100881610-B040001100881710 39.3 B040001100881410-B040001100881710 53.2 1.4 Elevation-change maps (rasuwa_post_vantor_dh.zip) file description rasuwa_dh_lg03_20260907_minus_wv03_20260827_2m_v1.0.tif 11-day change along the downstream valley rasuwa_dh_wv02_20260908_minus_lg02_20260906_2m_v1.0.tif 2-day change over the source area (consistency check) 2. Methods DEMs were generated from the Level-1B images with the NASA Ames Stereo Pipeline (ASP 3.8.0-alpha; Beyer et al., 2018; Shean et al., 2016). The WorldView-3 and WorldView Legion 3 images were orthorectified onto the Copernicus GLO-30 DEM before correlation, with the stereo processing settings described in Bhushan and Shean (2021) and Shugar et al. (2021). DEMs were co-registered by translation to a common pre-event reference surface on stable ground, excluding surfaces that changed during and following the 2026-08-26 event. Each WorldView Legion 3 DEM was co-registered to an initial WorldView-3 median composite. Composites were built with dem_mosaic as priority-ordered and weighted-mean mosaics. 3. Known issues Partly cloudy images: DEMs created from coverage gaps in at least two images, with possible artifacts near cloud edges. The 2026-08-27 WorldView-3 median composite is less reliable where few pairs overlap (see its count layer); its southernmost ~2.5 km (one pair) is biased high. Steep, shadowed or texture-poor terrain has gaps and localized errors. Pair DEMs and the WorldView-3 median keep their native grids, offset from the other products by a fraction of a pixel. 4. License and acknowledgments CC BY-NC 4.0. Original Level-1B Imagery (c) 2026 Vantor. This work utilized data made available through the NASA Commercial Satellite Data Acquisition (CSDA) Program and the Vantor Open Data Program. Funding: NASA award 80NSSC24K1633 (HiMAT-2B) and NASA award 80NSSC26K0856 (DSI24). Products were generated on a rapid disaster-response timeline and are provided without warranty. 5. Citation Shean, D., and Bhushan, S. (2026). Post-event optical stereo DEMs (WorldView-2, WorldView Legion 2/3, WorldView-3) for the 2026-08-26 Rasuwa (Langtang Lirung) ice-rock avalanche, Nepal (v1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.22842746 References Beyer, R. A., Alexandrov, O., and McMichael, S. (2018). The Ames Stereo Pipeline: NASA's open source software for deriving and processing terrain data. Earth and Space Science, 5, 537-548. https://doi.org/10.1029/2018EA000409 Bhushan, S., and Shean, D. (2021). Chamoli Disaster Pre-event 2-m DEM Composite: September 2015 (Version 1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.4554647 Shean, D. E., Alexandrov, O., Moratto, Z. M., Smith, B. E., Joughin, I. R., Porter, C., and Morin, P. (2016). An automated, open-source pipeline for mass production of digital elevation models (DEMs) from very-high-resolution commercial stereo satellite imagery. ISPRS Journal of Photogrammetry and Remote Sensing, 116, 101-117. https://doi.org/10.1016/j.isprsjprs.2016.03.012 Shugar, D. H., Jacquemart, M., Shean, D., Bhushan, S., et al. (2021). A massive rock and ice avalanche caused the 2021 disaster at Chamoli, Indian Himalaya. Science, 373(6552), 300-306. https://doi.org/10.1126/science.abh4455