Glacial Lake Outburst Flood (GLOF)

A New Study has just come out about Glacial Lake Outburst Floods (GLOFs), and it’s a big deal because these floods can put millions of people at risk around the world. For the first time ever, researchers have tried to figure out where these floods might happen. They looked at how big the glacial lakes are and how many people live downstream from them, and it turns out that more people are in danger than we thought. It’s a global effort to map out the areas most at risk from these potentially dangerous floods.

What are Glacial Lake?

Glacial lakes, like South Lhonak Lake, are big water bodies found near, above, or below melting glaciers.
As these lakes get bigger, they become riskier. This is because they’re often held back by unstable ice or a dam made of loose rocks and debris.
If the boundary holding these lakes together breaks, there’s a serious risk of a Glacial Lake Flood (GLOF). This means tons of water rushing down the mountain sides, potentially causing floods downstream.

Causes of GLOF

Glacier lake outburst floods (GLOFs) can happen due to various reasons, like earthquakes, heavy rains, and avalanches.
Since these lakes are often situated in steep mountainous areas, landslides or avalanches can directly fall into them, displacing water and causing overflow.
A tragic incident took place in 2013 in Kedarnath, Uttarakhand. Flash floods and GLOF floods, triggered by the Chorabari Tal glacial lake, led to a devastating situation, resulting in the loss of thousands of lives.

Key Highlights

Vulnerability: Up to 15 million people are at risk of facing catastrophic flooding from glacial lakes, which could burst their natural dams at any moment. The greatest threat is for those living in mountainous regions in Asia and South America.

Most at Risk: Around 9.3 million people, or 62% of the globally exposed population, are located in the high mountain Asia (HMA) region. In Asia alone, nearly one million people live within just 10 km of a glacial lake. The majority of those at risk are in India, Pakistan, Peru, and China, accounting for over half of the global population at risk.

Dangerous Basins: The most dangerous glacial basins are found in Pakistan (Khyber Pakhtunkhwa basin), Peru (Santa basin), and Bolivia (Beni basin). These basins are home to 1.2 million, 0.9 million, and 0.1 million people, respectively, who could be exposed to Glacial Lake Outburst Flood (GLOF) impacts.

Climate Change Impact: Glaciers across the Andes in South America have rapidly melted over the past two decades due to climate changes, increasing the risk of GLOFs.

Threat to India: In the Himalayas, 25 glacial lakes and water bodies have seen an increase in water spread area since 2009. There’s been a 40% increase in water spread in India, China, and Nepal, posing a significant threat to seven Indian states and Union Territories. The most vulnerable are Jammu and Kashmir, Ladakh, Himachal Pradesh, Sikkim, Assam, and Arunachal Pradesh.

Rapid Onset and Impact: The rapid onset and high discharge of GLOFs often leave little time to effectively warn downstream populations. This poses a significant challenge for communities located within 10-15 km of the source lake.

Impact: The floods that follow can be powerful enough to destroy vital infrastructure, posing a catastrophic threat to people’s lives, livelihoods, and regional infrastructure.

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:

Identifying Dangerous Lakes:

Look out for lakes that could pose a threat based on past events, observations, and geological features.
Use technology like Synthetic-Aperture Radar to spot changes, especially during the monsoon season.

Using Technology for Early Detection:

Employ Synthetic-Aperture Radar imagery to automatically detect changes in water bodies.
This helps in identifying new lake formations, especially during the monsoon.

Structural Measures to Manage Lakes:

Reduce water volume through methods like pumping or siphoning.
Consider creating tunnels through moraine barriers or under ice dams.

Example of Successful Intervention:

In 2014, an Expert Task Force, with the Army, managed a potential flood in Ladakh by using explosives to channel water from the river.
Controlled blasting and manual debris removal were crucial in preventing a disaster.

Prohibiting Construction in High-Risk Areas:

Avoid building in areas prone to disasters, reducing risks without additional costs.

Land Use Planning:

Implement regulations for land use planning, especially in downstream areas.
Monitor infrastructure development during and after construction.

Training Local Teams:

Establish local teams to assist in planning and setting up emergency shelters.
Train them to distribute relief packages, identify missing people, and address basic needs like food, healthcare, and water supply.

Early Warning System:

Implement a reliable early warning system in vulnerable zones to alert people in advance.

Emergency Medical Response:

Set up Quick Reaction Medical Teams, mobile field hospitals, Accident Relief Medical Vans, and heli-ambulances in areas not easily accessible by roads.