What is glacial lake outburst flood and why does it occur? Everything you need to know about the floods in Uttarakhand
On 7th February 2021, a significant part of the Nanda Devi glacier broke off in Chamoli district located in Uttarkhand, resulting in massive floods that led to ten deaths and one hundred and fifty people reportedly missing. This incident brought all our attention to the massive floods that happened in Uttarkhand in 2013.
Now let us understand more about what a glacial lake outburst flood is.
Glacial lake outburst flood or the acronym GLOF is a term used to describe a quick or sudden release of water contained in a glacier lake. This quick release of water can happen due to a variety of causes. One of the major factors behind a glacier retreat is climatic changes that are usually observed in high-latitude and high-altitude regions across the whole world.
The usual characteristics of GLOFS are extreme peak fusillades or discharges of glacier lakes, often several times in excess, with a great transport potential that can turn into a high flow-type movement.
The three main features of GLOFS, according to antarticglaciers.org are as follows:
1.They involve rapid sometimes cyclic releases of water from the glacier lakes.
2. The massive flow of water does not stop quickly, they usually last for many hours or for some days in case of massive outbreaks.
3.The aftermath of such outbreaks results in large downstream river discharges which are typically controlled by the magnitude of the outbreak.
Now let us understand the reasons why glaciers break.
Why does a glacier break?
There are several factors behind a glacier break:
It can happen to a buildup of water pressure or due to an earthquake or cryoseism (An earthquake caused by some sudden glacial movements). It can also happen due to an avalanche of rock or heavy snow. Sometimes volcanic eruptions under the ice could be the reason for a glacier break. The direct or straightaway causes of glacial outbursts are connected to earthquakes, heavy rainfall, melting of snow, long-term dam degradation, and so on.
What is the reason behind the sudden glacier break in Uttarakhandhe e?
Although the exact reason for the massive glacier outbreak is yet to be confirmed, it is observed that heavy construction works or human intervention in eco-sensitive regions of the Himalayas are responsible for the massive climate change observed there, which leads to the breaking of glaciers. Many senior climate and energy campaigners believe that the heavy construction works happening in eco-sensitive regions of the Himalayas should be avoided. Although nobody can point fingers and claim that human intervention is the only factor responsible for these outbreaks, GLOFS can also occur due to climate change caused by global warming, which has become a very serious issue now.
A quick recap of the floods that happened in Uttarkhand in 2013
In June 2013, a grave natural disaster struck the region of Kedarnath in the form of heavy rains of great magnitude. Due to a cloudburst, the banks of the Chorabhari lakes collapsed resulting in heavy floods that led to the deaths of many animal and human lives. It also resulted in the widespread destruction of agricultural lands and the loss of infrastructure. The disaster struck Kedarnath after a heavy downpour, unlike the glacier break that happened recently which occurred on a bright sunny Sunday. Due to the bad weather during the Kedarnath floods, the rescue and relief operations were delayed resulting in many casualties. Because of the mortifying floods and landslides, it became the nation's worst natural disaster since the tsunami that occurred in 2004.
The rainfall received in Uttarkhand during the month of June was way greater than the rainfall the state usually received. According to the statistics provided by Wikipedia, more than 5,700 people were declared dead, including 934 residents. The mass destruction of the bridges and the roads led to 300,000 pilgrims and tourists being trapped in alleys. The landslides caused by floods severely damaged houses and structures, taking the lives of people who were trapped in their houses. All the villages and settlements like Gaurikund and the market town of Ram Bada were severely affected.
Over 70,000 people across different regions in Uttarkhand were trapped due to damaged and blocked roads. People in other pilgrimage centers like the Valley of Flowers, Roopkund, and Sikh pilgrimages were stranded over for more than three days with only a little food to survive. The roads were severely damaged at 450 places resulting in huge traffic jams, which also caused many cars and other vehicles to be washed away. Many important highways that connected important regions were washed away. Since this disaster happened during the peak months of tourism, many tourists were stranded with only little ration to survive. On 18th June, more than 12,000 people were stranded at Badrinath, the temple located across the banks of the Alaknanda river. Bodies of people who were caught in the floods were found in different regions across Uttarkhand. Making it the worst natural disaster that happened in recent years.
Let us pray for all the families who lost their dear ones and pray that this does not happen again. Let us also try to avoid construction activities at eco-sensitive zones, as human intervention is one of the major causes of such disasters. Let us respect mother earth and her resources and live with nature more harmoniously.