Glacier collapse triggers a dam burst in India

More than 170 people are feared dead after a glacier collapse triggered floods and damaged 2 dams in north India.

The incident occurred on Sunday, February 7, 2021, in Uttarakhand state, northern India. A section of a Himalayan glacier detached and moved downwards at a very high velocity impacting a river and causing high waves and intense floods. The water flow swept away a dam and damaged another one. 28 people have been reported dead and more than 150 are still missing.

Most of the victims are believed to be laborers working at nearby hydropower plants. Rescue teams were deployed at multiple sites that have been affected. The teams included military personnel and helicopters that assisted the challenging efforts. 15 people were trapped in a long tunnel but they were fortunately rescued the following day with authorities focusing on a second tunnel that has been blocked by debris.

The area is remote and steep, therefore, what actually had happened was not apparent. Utilizing satellite imagery, scientists managed to derive what triggered the floods and the dam failure. Data showed that a large glacier crack had formed at an elevation of 5,600 meters on the Nanda Ghunti mountain. Images showing the crack were collected on February 2, 5 days before the disaster (a close look can be found below). Searching previous images, it was found that the crack initiated in early 2020. According to the research team, this crack triggered the glacier collapse. In particular, a massive block (measuring more than 2 million m³) detached from the mountainous slope and traveled about 2km before impacting with high velocity an ice deposit.

By traveling this distance, the block carried away debris and ice and accumulated massive amounts of energy before striking the valley. The impact caused the ice to melt and triggered a vast debris flow that eventually caused extensive flooding and damaged the dam sites. 

Local officials mentioned that the debris flow also swept away a bridge that linked 13 villages isolating them. Authorities delivered food packages to the 2500 villagers affected via helicopter missions.

Some believe that the current incident is associated with climate change and the fact that the glaciers are melting faster than before. Others suggest that the intensive infrastructure development in the Uttarakhand region has impacted the unique Himalayan ecological system resulting in extreme phenomena. There are 550 hydropower projects and dams in the Uttarakhand state, 58 of them associated with the affected region.  

According to the Columbia University Lamont–Doherty Earth Observatory, the lower-level glaciers in the Himalayan region are shrinking by 5 meters each year. Professor Dave Petley from Sheffield University in the UK, suggests that there is evidence to deduce that rising temperature could have contributed to the collapse even if it is fallacious to imply that a single incident is caused by climate change.