Scientists now say the Uttarakashi disaster was not caused by a cloudburst. According to meteorological data, the region received only 8–10 mm of rainfall on August 4–5—far below the 100 mm threshold that defines a cloudburst. Former Wadia Institute scientist Dr. D.P. Dobhal explained that the disaster likely resulted from a flash flood triggered by the sudden breaching of an ice-dammed or landslide-formed temporary lake above the forested area behind Dharali. He noted the presence of loose debris, such as ice, rocks, and mud, similar to what was seen in the 2021 Chamoli disaster.
The region is marked by narrow valleys and steep mountains, making it susceptible to glacial hazards. If a glacier collapses into such a lake, it can trigger a fast-moving surge of debris-laden water. This type of flow, containing grey-colored silt and black floodwater, matches the visuals emerging from Dharali.
Dr. Manish Mehta of the Wadia Institute confirmed that only satellite imagery will provide a definitive explanation. But based on previous disasters, experts suspect the cause could be glacial collapse, landslide-dammed lake bursts, or flash floods—rather than conventional cloudburst events.
