ISRO Satellite Images Reveal Uttarkashi Flood Destruction, Cause Still Undetermined
Post-disaster satellite images display a vast fan-shaped spread of mud and debris, roughly 20 hectares in area, at Dharali village, where the Kheer Gad stream meets the Bhagirathi river.
As experts continue to study the reason behind the fatal Uttarkashi flash floods, fresh satellite imagery from the Indian Space Research Organisation (ISRO) has shown the large-scale devastation in the Himalayan belt.
Captured by the Cartosat-2S satellite, the high-resolution pictures taken on August 7, post-disaster, revealed a prominent fan-shaped deposit of silt and debris—covering around 20 hectares (750 m x 450 m)—at Dharali village, where Kheer Gad stream merges with the Bhagirathi river.
The National Remote Sensing Centre (NRSC) in Hyderabad, a division under ISRO, carried out a rapid assessment by comparing the August 7 images with pre-event cloud-free imagery dated June 13, highlighting the extent of the damage.
The visuals clearly show the aftermath of the deadly flash floods—widened stream pathways and changes in the river’s physical layout, pointing to significant destruction of life and infrastructure. The impact is visible with many buildings missing in the affected area, likely submerged or washed away in the heavy debris-laden water flow. “Several buildings seem to be buried under mud and debris in Dharali village. The satellite images will support ongoing rescue and relief efforts to locate stranded individuals and reconnect the cut-off region,” the space agency noted, highlighting the rising threat that Himalayan settlements face from natural disasters.
However, ISRO stated that researchers are still working to determine the exact cause of the flash floods, and investigations are in progress. A cloudburst in the upper areas was initially believed to be the trigger; however, no solid data has confirmed it yet.
Earlier, a separate analysis conducted by Uttar Pradesh-based earth observation and satellite data analytics company Suhora Technologies dismissed Glacial Lake Outburst Flood (GLOF) as the cause behind the flash floods. The company cross-checked the high-resolution ISRO images with its own glacial lake records and confirmed there was no glacial lake upstream of Dharali village. “We obtained Synthetic Aperture Radar (SAR) imagery at 11:01 PM on August 5 via our SPADE platform, which gave us near real-time visuals, enabling timely and precise evaluation of the disaster,” the company mentioned in a statement.
The disastrous flash floods that struck on Tuesday brought debris-filled torrents over Dharali and Harsil villages in Uttarkashi district of Uttarakhand, sweeping away houses, buildings, bridges, and roads, and resulting in multiple casualties. With over six people confirmed dead and many still unaccounted for, the powerful water waves destroyed everything in their path. Rescue operations are ongoing despite continuous rainfall, with the India Meteorological Department (IMD) forecasting heavy rains to persist in the state until at least August 11, as the southwest monsoon remains active in the region.
