Glacial lake outburst flood

by Luca Catalano Gonzaga

The climate change correlated with increasing temperature of the planet is causing the retreat of glaciers in the mountain range of the Himalayas, creating a worrying rise of the water level. If a glacier melts, a lake is created in the bottom moraine and the same sediments left by the glaciers act as a dam to the water. The lakes within them have long been in a precarious balance between the amount of water that comes from melting ice and the one that goes through the emissary streams. The increase in the Earth’s temperature, which led to a rapid melting of the glaciers in recent years, has altered this balance. The level of the lakes has grown rapidly and the moraines, which act as a dam,may not withstand the thrust of water. The arrival of the monsoons, with the abundant rains, worsens the situation, with the risk of flooding the underlying valleys. The Lake Tsho Rolpa, the largest and most dangerous glacial lake in Nepal that is located in the Rolwaling Valley, approximately 30 km southwest of Mt. Everest. It has formed over the last forty years as the Trakarding Glacier has stagnated, melted and retreated. The lake, which is at an elevation of 4.580 metres, is approximately 3 km long, 0.5 km wide and up to 135 m deep. It is retained by a natural moraine dam that is unstable and threatens to burst. If the dam is breached, the resulting flood of approximately 80 million cubic metres of water, would cause serious damage for 100 km or more downstream, threatening as many as 6000 lives. It also threatens the construction site of a 60 MegaWatt hydroelectric project and other infrastructure. The damage would have a serious impact on the economy of Nepal. While waiting for the engineers to be able to find a way to lower the water level, The lake Tsho Rolpa is currently surrounded with sensors and alarms that are connected to sirens in the villages in danger. They can give only a 10 minute advance notice which is too short for a possible evacuation. Whole families of farmers living in the Rolwaling Valley, are therefore seriously worried about their own and their children’s future survival. Still, they are forced to remain in their villages, as the only source of income, besides the care of yaks, is the cultivation of potatoes and they do not have any other place to go. (text by Luca Catalano Gonzaga).


A selection of photos from the archive of Luca Catalano Gonzaga is available as collector’s prints. The goal of print selling is to contribute to the realization of the photographic projects of Witness Image that narrate the great transformations of our time.