One of the most dangerous glacial lakes in Nepal is the Tsho Rolpa Lake at an altitude of about 5000m and whose size increased from 0.23 sq.km. in 1957 to 1.65 sq.km. by 1997. Tsho Rolpa was estimated to store approximately 90-100 million cu.m. in 1997, a hazard that called for urgent attention. Besides the downstream communities, the 60MW Khimti hydropower plant was under threat. To reduce the risk of a glacier lake outburst flood (GLOF), the water level in the lake was lowered by three meters by cutting open channel in the moraine. In addition a gate was constructed to allow water to be released as necessary. An early warning system was established in 19 villages downstream of the Rolwaling Khola on the Bhote/Tama Koshi River, to give warning in the event of a Tsho Rolpa GLOF. Local villagers have been actively involved in the design of this system and drills were carried out periodically. The risk of GLOF now has been reduced by 20%. The complete prevention of a GLOF at Tsho Rolpa necessitates further reducing the lake water by as much as 17 m.