Context: Recently, NDMA has issued guidelines to reduce disasters related to Glacial Lake Outburst Floods (GLOFs). Recently GLOF is suspected to have caused the flash floods in Uttarakhand’s Chamoli.

What are Glacial Lake Outburst Floods(GLOFs)?

• It refers to the flooding that occurs when the water dammed by a glacier or a moraine is released suddenly.
• It is a type of outburst flood. It occurs when water dammed by a glacier is released. In other words, it’s an outburst that happens when a dam containing a glacial lake fails.

Note: An event similar to a GLOF, where a body of water contained by a glacier melts or overflows the glacier is called a jökulhlaup.

How does GLOF happen?

• Retreating glaciers, like several in the Himalayas, usually result in the formation of lakes at their tips, called proglacial lakes. It is often bound only by sediments and boulders.
• If the boundaries of these lakes are breached, it can lead to large amounts of water rushing down to nearby streams and rivers. It gathers momentum on the way by picking up sediments, rocks, and other material, and resulting in flooding downstream
• According to National Disaster Management Authority (NDMA), Climate change is facilitating the glacial retreat in most parts of the Hindu Kush Himalayas. It is resulting in the formation of numerous new glacial lakes. Due to that, this area has become prone to GLOFs.

NDMA Guidelines for Reducing GLOFs
The NDMA, headed by PM, had issued detailed guidelines on how to reduce and deal with disasters caused by GLOFs:

• Identify and Mapping Dangerous Lakes: Potentially dangerous lakes can be identified. This identification will be based on field observations, past events, geomorphologic and geotechnical characteristics, etc.
• Use of Technology: It has recommended the use of Synthetic-Aperture Radar imagery. It will automatically detect changes in water bodies, including new lake formations, during the monsoon months.
• Structural Measures: It recommends reducing the volume of water with various methods to manage lakes structurally. Methods are pumping or siphoning out water and making a tunnel through the moraine barrier or under an ice dam.
• Example: In 2014, a landslide occurred along Phuktal (tributary to Zanskar river) in Kargil district of Ladakh. It led to a potential flood situation. The NDMA created an Expert Task Force which along with the Army used explosives to channel water from the river. It used controlled blasting and manual excavation of debris for this purpose.
• Constructions and development in High prone areas should be prohibited. It is a very efficient means to reduce risks at no cost.

Land Use Planning: Land use planning regulations need to be developed. In downstream areas, Infra. development should be monitored prior to, during, and after the construction.

• Trained Local Manpower: Apart from specialized forces such as NDRF, ITBP, and the Army, there is a need for trained local manpower. These teams will assist in planning and setting up emergency shelters, distributing relief packages, identifying missing people, and addressing the needs for food, healthcare, water supply, etc.
• Early Warning System: A robust early warning system in vulnerable zones should be put in place.
• Emergency medical response team: Quick Reaction Medical Teams, mobile field hospitals, Accident Relief Medical Vans, and heli-ambulances should be set up in areas inaccessible by roads.
• Psychological Counselling: The guidelines also call for psychological counseling of victims.