There is a glacier lake up in Rolwaling Himal above the settlement of Bed ing that is about to rupture. An earthquake or avalanche is likely to break the weak, moraine dam which props up the lake, and releases 71 million cubic metres glacial melt water.
If the water is released slowly, damage will belimited. But chances are that the marine collapse will be sudd en, in which case Nepal will experience a Glacier Lake Outburst Flood, or GLOF, which is greater than all the GLOF phenomena of recent decades.
The glacier lake is known as Tsho Rolpa, and is at the headwaters of the Rolwaling Khola in Dolakha District, northeast of Kathmandu, below the Gauri Shankar massif. Over the last four decades, glacial meltfrom the TrakrardingGlader has collected in a lake, held back by the loosely filled debris of the glacier´s end-moraine. The glacier is receding fast, andit is in the process of releasing a large volume of water which goes into the lake.
Satellite data, aerial observations and on-site investigations by the Water and Energy Commission Secretariat (supported by Japanese funding) show that the size of Tsho Rolpa has increased relentlessly. The surface area of the lake was about .23 sq km in 1959, while in 1993 it had expanded to 1.4 sqkm. The elongated lakeis today 3 km in length and has an average, width of half a kilometre. Towards themiddle, one measurement showed a depth of 132 m.