A glacial lake outburst flood (GLOF) in Bhutan has raised concerns about flooding in some parts of West Bengal and Assam. Authorities have issued high alerts for the area following the sudden release of water which has raised fears about river levels rising and flash flooding in downstream areas. Over 10,000 people in West Bengal have been relocated to safer areas.

Bhutan Glacial Lake Outburst Flood

The outburst happened at Shintaphu Lake in Bhutan’s Gasa district. This is below Wakila Mountain and large amounts of water were released into the downstream areas. This includes the Mo Chhu river system which drains into the Sankosh River.

Due to the sudden outburst of water there are concerns for flash flooding in downstream areas. Both countries are keeping a close eye out. This is to reduce the risk of loss of life.

Bridges Washed Away

The powerful flood has caused damage to the infrastructure in Bhutan, including the popular Gasa Tshachu hot springs. There have been initial reports that two Bailey bridges have been washed away.

There has also been damage to parts of the road between Laya village and it has been blocked. It has been closed and the extent of the damage will be assessed. Due to the powerful current and lack of visibility the full extent of damage isn’t clear yet.

West Bengal on High Flood Alert

Authorities across West Bengal have put flood warnings on high alert for vulnerable areas.

Advice has been sent to residents in the Darjeeling hills, Terai and Dooars areas asking them to be careful and relocate to safer areas if they live in flood areas. Over 10,000 people have been relocated with thousands entering temporary shelters and safe areas.

The National Disaster Response Force (NDRF), State Disaster Response Force (SDRF), police and local authorities have been mobilised. Temporary centres have been set up with basic amenities.

Assam on High Alert

• The Assam government have also put themselves on high alert. Particularly in areas of Dhubri where they may be affected by downstream flooding.
• The Sankosh River runs through the area so those living nearby are at risk of sudden flooding. Officials and disaster management are keeping an eye on the river.
• Initial reports from the Assam State Disaster Management Authority said that the water levels in the Sankosh River were calm in the early morning on Friday. They are, however, still keeping a close eye on the river in case of sudden rises.

What is a Glacial Lake Outburst Flood?

A Glacial Lake Outburst Flood is a natural disaster. This occurs when a glacial lake releases a large amount of water suddenly. This happens when the natural barrier of the lake weakens or breaks.

Glacial lakes form when glaciers melt leaving large amounts of water trapped behind natural barriers created by rock, soil and ice. When these barriers break large amounts of water can rush down the river quickly creating devastating flash flooding.

This can cause damage to bridges, roads, buildings, farmland and villages. Mountainous areas in the Himalayas are prone to GLOF. This is due to the barriers being delicate and the steep slopes.

Concerns of Himalayan Flooding

• The latest glacial lake outburst in Bhutan has raised concerns further about Himalayan flooding. Those who live downstream from glacial lakes are at risk of sudden flooding. This can be particularly dangerous during times of changing weather.
• Experts have often stressed how important it is to have early warning systems in place. Monitoring glacial lakes that could be dangerous and working together between neighbouring countries.
• As authorities are looking into the situation in Bhutan, residents in vulnerable areas of West Bengal and Assam are being advised to follow the official advice. They should not go near the riverbanks and avoid flood areas.