The National Centre for Hydrology and Meteorology (NCHM) is exploring measures to bring down the water level at Thorthomi glacial lake in Lunana. This initiative is timely as we face one of the gravest risks posed by climate change.

Situated in the mountains, our vulnerability to the impacts of a glacial lake outburst flood (GLOF) is significantly high. The threat from Thorthomi, the most dangerous among Bhutan’s 17 potentially hazardous glacial lakes, is particularly alarming. Experts have aptly termed it a “ticking time bomb”.

What we know is that Thorthomi is rapidly expanding due to melting ice amid increasing temperatures, a direct consequence of climate change. The situation is critical.

If the current climatic conditions persist and the moraine dam collapses, the water pressure from Thorthomi could surge into Rapstreng, potentially triggering a massive GLOF. Such an event would be catastrophic, not only for the immediate area but also for downstream communities and the nation at large.

Thorthomi now is a fully formed glacial lake with only a few chunks of ice floating. It is separated from Rapstreng Tsho by a thin moraine dam. Alarmingly, the size of the narrowest crest of this moraine dam has decreased from about 45 metres in 2008 to approximately 33 metres in 2019. In a worst-case scenario, if the moraine dam collapses, Thorthomi would pour into Rapstreng, triggering a combined GLOF with an estimated flood volume of 53 million cubic metres of water.

The memory of the 1994 Lugge Tsho outburst, which caused untold damage and claimed lives, serves as a stark reminder of what could happen when twice the volume and force of water come tumbling down, wiping out everything on its way.

As temperatures rise, so should our preparedness. The question that we must ask ourselves is: Are we doing enough? The current efforts by the NCHM to mitigate the risk at Thorthomi are commendable, but they are only the beginning.

There should be a continuous and detailed monitoring of glacial lakes, particularly Thorthomi. This involves not just seasonal assessments but also real-time monitoring systems that can provide early warnings. Automated sensors and a network of monitoring stations have enhanced our ability to predict and respond to potential GLOFs. But we certainly can, and must do a lot more.

Community-based disaster preparedness programmes are crucial. Local communities, especially those residing in vulnerable areas, must be educated about the risks and trained in emergency response procedures. This includes conducting regular drills, developing evacuation plans, and ensuring that communication channels are robust and effective.

Strengthening and constructing barriers or diversion channels can help manage the flow of water in the event of a GLOF. Improving the resilience of existing infrastructure such as roads, bridges, and buildings can reduce the potential damage and facilitate quicker recovery.

Have we done enough?

The government must also prioritise and allocate sufficient resources for GLOF risk mitigation. This includes not only funding for monitoring and infrastructure projects, but also investing in research and development. Investments in these areas will only grow in the future. Are we looking that afar?

Facing this challenge is not just about mitigating a disaster; it is about securing the future of our nation.

Advertisement