• A glacial breach in Uttarakhand’s Chamoli district on February 7 triggered an avalanche and flash floods in the Alaknanda river system. 

    • The Snow and Avalanche Study Establishment (SASE) of the Defence Research and Development Organisation is still investigating the matter and has not yet zeroed in on the exact reason for the flooding as yet.

    • A glacial breach likely caused an avalanche and breached a lake uphill of Raini village in Chamoli district, located on the boundary of the Nanda Devi biosphere reserve, experts say.

    • The breach led to water surge in Dhauliganga river and its tributary Rishiganga.

    • The Rishi Ganga hydel plant on the Rishiganga river was the first to be hit by the breach in the district. An upstream dam – Rishi Ganga – constructed to divert water was washed away.

    • The second major project affected by the flooding was the NTPC Tapovan hydel plant on the Dhauliganga river. As many as 148 workers are missing from the NTPC project.

    • Sudden outburst of a glacial lake with debris shows that degradation of the forest cover in upper reaches and faster melting of snow due to climate change, experts said. 

    • Warmer January and February could have resulted in the formation of the glacial lake. 

    • The back-to-back dams (Rishi Ganga and Tapovan dams were within 10 kms of each other) block natural flow of rivers that helps in disbursing heavy debris.

    • Over the last three decades, major natural disasters have hit the state of Uttarakhand. Some of them are:

    1. 1991 Uttarkashi Earthquake: An earthquake of 6.8 magnitude hit the undivided state of Uttar Pradesh in October 1991 in which at least 768 people were killed and thousands of homes destroyed.

    2. 1998 Malpa Landslide: The small village of Malpa in Pithoragarh district was wiped in the landslide in which about 255 people, including 55 Kailash Mansarovar pilgrims, were killed. The resulting debris partially blocked the Sharda river.

    3. 1999 Chamoli earthquake

        a. An earthquake of 6.8 magnitude hit Chamoli district killing over 100 people.

        b. The adjoining Rudraprayag district was also heavily affected.

        c. Several ground deformations were reported as a result of the earthquake, and landslides and changes in water flow were also recorded. Cracks were observed in roads and on the ground.

    4. 2013 North India Floods

        a. In June 2013, a multi-day cloudburst centered on Uttarakhand caused devastating floods and landslides.

        b. According to the state government, more than 5,700 people were presumed dead in the disaster.

        c. As bridges and roads were destroyed more than 3 lakh people were trapped in the valleys leading to the Char Dham pilgrimage sites. 

(The author is a trainer for Civil Services aspirants. The views expressed here are personal.)