A massive glacial flood originating from Nanda Devi glacier in Indian state of Uttarakhand Sunday morning has caused widespread destruction and damages in the downstream areas. Eighteen people were killed in the disaster while 165 others are still missing. Though exact cause of what triggered the mountain flood is yet to be ascertained, breaking of ice dam and releasing of huge volume of water behind it has been suspected. A glacial lake of sorts might have been formed up in the mountain and was held in place by the moraine of ice blocks or loose soil that acted as a dam. Here, scientists suspect the effect of global warming which is contributing to accumulation of more water in the glacial lakes or melting of ice boulders holding the water in place or bringing an avalanche.
And one can imagine what happens when huge amount of water rushes down the steep slope, carrying all kinds of debris along with it. Video footages show white flashfloods crashing down the steep hills in great speed and washing away everything standing on the way. Some settlements lying too close to the riverside were swept away before people could know what was happening and run to safety. People easily get caught unprepared also because this is not the rainy time of the year and usual floods are unexpected. The glacial flood is reported to have destroyed a powerhouse on the bank of the Alaknanda River and caused damage to another under power plant construction along the bank of the Dhauliganga River. Dozens workers were trapped in the tunnel of the Dhauliganga plant. Two dozen of them were rescued.
People living in valleys and plains downstream are called to evacuate but those living in the mountains and hills, too close to the flood path, might have caught unprepared. This event is a grim reminder of the fact that the glaciers and glacial lakes up in the Himalayan mountains are becoming unstable and dangerous in recent years due to climate change impact. The type of disaster that was unleashed from Nanda Devi might be lurking in many other places in India, Nepal and Bhutan and elsewhere along the Himalayan belt. This is an event of what the scientists had been warning for long. This is a disaster that Nepal should also learn a lesson from and try to stay prepared. Scientific observations have seen the melting and retreading of the Himalayan glaciers and the formation and expansion of glacial lakes.
Comparative satellite images analysed by agencies like the International Centre for Integrated Mountain Development (ICIMOD) show the increasing formation of glacial lakes and expansion of water volumes in them. As the effects of global warming continue, moraine dams of the glacial lakes will no longer be able to hold the vast amount of water. The ultimate result is the bursting of the natural dam and the release of disastrous flashfloods. In this regard, Nepal lies in a sensitive zone as it has hundreds, if not thousands, of glaciers and glacial lakes along the Himalayan range. Once such disaster takes place, several of which have happened in the past too, downstream areas will witness the devastation of widespread scale. Physical infrastructure such as roads, bridges, power plants, power transmission lines will be destroyed. Settlements, marketplaces, farmlands, schools and other structures also face threats. So, we need extensive studies about this topic and stay prepared for possible calamity.