Imja Tsho is a glacial lake created after melt water began collecting at the foot of the Imja Glacier on the lower part of the glacier in the 1950s. A 2009 study described this lake of melt water as one of the fastest-growing in the Himalayas. Held in place by a terminal moraine, Imja Tsho threatens downstream communities with the potential for a glacial outburst flood.