Context

The number of glacial lakes in the Sutlej river catchment is expected to almost double from 562 in 2019 to 1,048 in 2023, according to satellite data analysed in a recent study by the Centre for Climate Change of Himachal Pradesh Council of Science Technology-Environment (HIMCOSTE).

Key Highlights

• In recent years, the number of moraine lakes has increased in the Trans Himalayan region of Himachal Pradesh and Tibet due to the rapid reduction in the size of glaciers due to the impact of climate change.
• Climate change has affected the health of glaciers across the Himalayan region. As a result, the cryospheric cover over the Himalayan terrain is getting depleted.
• If the lakes go out of control for any reason, the rise in the water level of glacial lakes in the river valleys of Himachal Pradesh can be disastrous.

Glacial Lake Outburst Flood -GLOF

• It is a devastating natural phenomenon in which the dam of a glacial lake breaks and a large amount of water, ice and debris suddenly flows downhill. This phenomenon is becoming more common as the melting rate of glaciers increases due to climate change.
• India, especially the Himalayan region, is one of the countries most affected by the threat of glacial lake bursts. Such incidents have occurred several times in Uttarakhand. Examples: Kedarnath tragedy, 2013, Rishiganga Valley tragedy of Chamoli, 2021 and Nanda Devi tragedy, 2021 etc.

Causes of Glacial Lake Outburst:

• Climate change: Warming temperatures are causing glaciers to melt faster, forming and increasing the size of glacial lakes.
• Unstable dams: Dams that hold back glacial lakes are often made of ice, rock and debris, which can become unstable due to erosion, melting or seismic activity.
• Sediment: Sediment deposited in the lake can increase water pressure and destabilise the dam.

Effects of glacial lake outburst:

• Loss of life and property: Flash floods cause a large number of deaths and property losses.
• Damage to infrastructure: Roads, bridges and other infrastructure get washed away.
• Agricultural losses: Fields and crops get destroyed.
• Environmental impact: Rivers and streams get filled with silt and debris, causing damage to ecosystems.
• Displacement of communities: People in the affected areas have to migrate from their homes.

How to control glacial lake outburst:

It is difficult to completely prevent glacial lake outburst, but several measures can be taken to reduce its effects:

• Early warning systems: Developing advanced systems to monitor glacial lakes and detect signs of any instability.
• Controlled drainage: Creating controlled drainage channels to reduce the water level of glacial lakes.
• Construction of robust dams: Strengthening natural dams, where possible, to enhance their stability.
• Disaster management: Making plans to rescue people in case of a disaster and to carry out relief and rehabilitation operations in the affected areas.
• Alarm systems: Modern communication technology systems using smartphones can be used in place of traditional alarm systems.
• Combatting climate change: Reducing the rate of glacial melting by mitigating climate change.