Overview of Glacial Lake Outburst Floods (GLOFs) in the Himalayas

The phenomenon of Glacial Lake Outburst Floods (GLOFs) is increasingly threatening life and infrastructure in the Himalayan region, primarily due to rising global temperatures and subsequent glacial melt. The catastrophic events that struck Nepal and India illustrate the urgency of addressing these natural disasters effectively.

Recent GLOF Events

• On July 8, a significant GLOF event in Nepal caused flash floods along the Lende river, damaging infrastructure such as the China-built Friendship Bridge and affecting hydro-power plants, thereby reducing Nepal's power supply by 8%.
• This event highlighted the absence of an early warning system, as Chinese authorities did not provide timely alerts, despite the increasing number of supra-glacial lakes on the Tibetan side.
• Another GLOF event occurred in Nepal's Mustang district, and past events include the 1981 Cirenma Co and the 1985 Digi Tsho GLOFs, further emphasizing the need for trans-boundary collaborations in setting up early warning protocols.

Glacial Lakes in the Indian Himalayan Region (IHR)

• The IHR comprises 11 river basins with 28,000 glacial lakes, predominantly categorized into supraglacial and moraine-dammed lakes.
• Supraglacial lakes form on glacier depressions and are susceptible to summer melting, while moraine-dammed lakes are prone to sudden failures due to loose debris at the glacier's snout.
• Rising temperatures in 2023 and 2024 have exacerbated glacial melt, increasing the risk associated with these lakes.

Challenges and Mitigation Strategies

• Monitoring and assessing the risk of these lakes is challenging due to their inaccessibility, the lack of weather and water monitoring stations, and the large number of lakes situated above 4,500 meters.
• The NDMA has initiated proactive measures to manage GLOF risks, including the Committee on Disaster Risk Reduction (CoDRR) and a $20 million national program to prioritize 195 at-risk glacial lakes.

National Program Objectives

• Hazard assessment of each at-risk lake.
• Installation of Automated Weather and Water Stations (AWWS) and Early Warning Systems (EWS).
• Risk mitigation through water level management and retention structures.
• Community engagement in risk reduction efforts.

Scientific Expeditions and Technology

• States with glacial lakes are encouraged to lead scientific expeditions to assess risks and implement preventive measures using Indian technology and expertise.
• Successful expeditions have conducted bathymetry, Electrical Resistivity Tomography (ERT), UAV, and slope surveys, demonstrating the importance of community engagement in these efforts.
• Monitoring stations have been installed in Sikkim to provide real-time data, addressing the data-gap in the IHR cryosphere.

Future Directions

• Plans to expand the national program following the 16th Finance Commission's recommendations to include more lakes and enhance risk reduction strategies.
• Indo Tibetan Border Police (ITBP) are being oriented towards manual early warning roles in the absence of automated systems.
• Continued focus on integrating local communities and leveraging Indian scientific expertise to address GLOF risks effectively.