Lake Merzbacher

42°12′N 79°52′E / 42.200°N 79.867°E / 42.200; 79.867Lake typeGlacier lakePrimary inflowsGlaciersPrimary outflowsEngilchek RiverBasin countriesKyrgyzstanSurface elevation3,304 metres (10,840 ft)

Lake Merzbacher (Kyrgyz: Мерцбахер көлү) is a moraine glacier lake located in east Kyrgyzstan between the north and south Engilchek Glaciers in the Tien Shan Mountains.^[1] It is often called the "Disappearing Lake" because it drains every year as the ice melts, often causing a glacial lake outburst flood.^[2] The lake was named after a German explorer, Gottfried Merzbacher, who led an expedition in the area in 1903.^[1][3] An ice dam prevents the lake from draining through the majority of the year. However, when a hole finally melts through the dam, the lake drains within three days.^[3] When this happens, the lake's discharge can be up to 1000 m³ a second which causes destruction of infrastructure and creates major flooding downstream.^[1] It goes through this cycle of appearing, expanding and then draining annually.^[3]