Glaciers and glacial lakes in the Hindu Kush-Himalayas are essential natural resources. They are the source of rivers that provide freshwater to about one-third of the world's population. In the Nepal Himalayas, as in many of the other parts of the world, glaciers are receding and glacial lakes are forming as a result of current climate warming. Besides being a significant natural resource, glacial lakes have a potential to be the source of a natural disaster. If the moraine dams of a glacial lake fail, the water can burst out, leading to massive floods and debris flows with potentially extensive damage downstream, including loss of life, livelihoods, and infrastructure. There are many examples in Nepal in which loss of lives and property have occurred as a result of glacial lake outburst floods (GLOFs).
Supported by The World Bank Global Facility for Disaster Reduction and Recovery (GFDRR), and with additional support from the Swedish International Development Cooperation Agency (Sida) and the Norwegian Ministry of Foreign Affairs, ICIMOD developed a detailed multistep risk assessment methodology for glacial lakes and applied it in collaboration with national partners to assess the hazard posed by glacial lakes in Nepal. The assessment, carried out between September 2008 and May 2010, included mapping of glacial lakes, identification and ranking of critical (potentially dangerous) glacial lakes, and field investigations of high priority lakes. The aim was to develop recommendations for adaptation and mitigation against GLOF hazards (potentially dangerous lakes), and to contribute to development of a strategy to address future risks from GLOFs.