A preliminary analysis by ISRO's National Remote Sensing Centre (NRSC) has mapped the massive glacier collapse in the Tibet-Nepal border region that is believed to have triggered devastating flash floods. The "before and after" satellite images show significant changes on the glacier from floodwaters are believed to have originated.

The analysis used satellite data to map surface changes on the glacier near the Trishuli and Bhotekoshi river systems.

According to the preliminary analysis, the incident began with an ice-rock avalanche or landslide, resulting in the temporary blockage of a river. This was followed by the sudden release of impounded water and debris, triggering flash floods and a surge of heavy debris along the Trishuli River system.

The images of the avalanche were captured by ISRO using Resourcesat-2A-an Earth observation and remote-sensing satellite.

The satellite images show a wide area of disturbance in the high-altitude terrain near the glacier adjacent to the Trishuli, along with a swollen Bhote Koshi river and extensive flooding downstream

The NRSC is responsible for the acquisition and processing of remote-sensing satellite data, data dissemination, aerial remote sensing and decision support for disaster management.

Originating in Tibet, Trishuli is a major tributary of the Narayani River system in central Nepal and a popular destination for white-water rafting. Rivers originating in Nepal ultimately flow into the Indo-Gangetic plains.

Nepal on Wednesday came under the sudden force of a massive flood, leaving a massive trail of devastation, with multiple deaths and many people still missing. The country's northern parts bore the brunt with Rasuwa district along the China-Nepal border being among the worst-hit areas.

The initial flood surge may have passed but the authorities are on high alert for possible secondary flooding and other hazards. Experts say that debris and ice avalanches are said to have created temporary dams that may cause sudden secondary surges. (UNI)