Glacier lake outburst floods (GLOFs) have claimed numerous lives and have inflicted high costs in destroyed infrastructure and property in Nepal. Studies on GLOFs in Nepal have so far concentrated on an inventory of glacier lakes, documentation of previous GLOFs and largely qualitative descriptions of glacier lake properties. The strategy towards GLOFs discussed in this paper is first to identify indicators to assess the risk of glacier lake outbursts and then to prevent outburst floods by controlled lake drainage and to make use of the water stored in glacier lakes. Several techniques for glacier lake drainage are discussed and compared with the advantages of the Hydraulic Syphon Technique (HST) which is described in this paper in terms of system design, installation, operation and constraints of operation. Necessary preconditions for the use of this technique are detailed geotechnical investigations for the glacier lakes to be stabilized and the installation of a monitoring system for water level fluctuations and possible rapid mass movements into the lake. This requires the close cooperation of experts and institutions in the fields of snow and glacier hydrology, geotechnical and civil engineering.
