Imja Tsho and moraine damImja Tsho (elevation c. 5000 m) is one of many moraine-dammed lakes in the Himalaya, an their number and size are increasing year-on-year in response to the warming climate. Many such lakes pose a threat to human civilisation, since dams could fail catastrophically and without warning. The moraine at Imja Tsho is not as tall as many others, and the lake seems to be draining via a well-defined stable channel. Geophysical data by our colleagues at Reynolds International, suggest that much of the moraine is not ice-cored and therefore may be less vulnerable to failure than many . However, other researchers are concerned that moraine collapse is possible. We therefore need a detailed geophysical survey and detailed analysis of the sedimentary make-up of the moraine dam, and assessment of the risks posed by calving, rockfall and avalanche. This is especially important, following the earthquakes in April and May 2015. | |||
 Overview of Imja Tsho, showing frozen lake, broad irregular terminal moraine, well-defined lateral moraines and the main outflow from the lake. |  The lake seen from the right-lateral moraine, with lateral morainic trough on the right at a higher level. The lake still carries a winter ice-cover. |  The lake seen from the left-lateral moraine, with plumes of wind-blown dust rising from the fine particles in the moraine. |  Telephoto of the moraine dam, showing its hummocky appearance and kettle holes with ponds, indicative of the presence of an ice core in places. |
 The outflow from the lake was quite small in this mid-May picture, but jumping across it was hazardous owing to the presence of ice under the debris. |  The view of the terminal cliffs of Imja Glacier from the left-lateral moraine, with more extensive lake-ice break-up, and wind-blown dust in the air. |  Telephoto of a tongue of ice extending into the lake. The dark debris indicates that ice is melting beneath. The lake is largely underlain by dead glacier ice. | |
| Photos Michael Hambrey, April-May, 2003 | |||