The Nepal government announced it had finished draining the Imja glacier lake in Everest region on 23 November.
Imja lake was in danger of flooding villages, bridges and trekking trails downstream.
Imja is one of the biggest glacial lakes in the Everest region of Nepal Himalaya at 5,010 meters above sea level. Since 1960 the small lake has increased to 1.28 square kilometres and 150 metres deep.
Imja lake is one of the six highly dangerous glacial lakes in Nepal.
It took more than six months for about 150 people including 40 military personnel and local Sherpas to construct an outlet and release almost four million cubic metres of water. The water level of lake–originally 149 metres deep – fell by 3.4 metres.
The outlet channel built by the Nepal Army in Imja glacial lake.
Nepal has thousands of glacier lakes. Many of these are filling up fast because of warming temperatures and melting glaciers.
Glacier lakes have burst their banks 24 times in Nepal since the 1960s, three of which were in the Dhud Koshi river basin in the Everest region.
The Nepal government set up flood risk reduction project, supported by the Global Environment Facility and United Nations Development Programme. Early warning systems have been installed in six settlements on the Everest trekking trails to send flood warnings to people downstream.
Nang Thume Sherpa, member of glacier lake task force, shows the early warning system installed in Fakding village, Solukhumbu. The early warning system will send automated messages from from a sensor installed in Imja lake.
Tourists have suggested the government shift trails on Everest to higher places so trekkers and porters climbing the mountain are safe from potential glacier lake floods.
Namche Bazaar, the gateway to Everest, Solukhumbu district.
Ajit Rai and his wife Ranjita Rai work as labourers in Dengboche village between Imja glacier and Everest Base Camp. “Last year a small flash flood triggered from Lotse glacier that mixed with Imja rive. Although it only destroyed one bridge near Dengboche, it has made me to think more about the safety of my family,” said Ajit.
Kalma Lama, from Lukla town, runs a shop in Dengboche. She is happy that the lake has been drained. She has already experienced a small glacial lake outburst flood from Lotse glacier lake last summer. “Although there was no loss from the flood, the Imja River is terrifying,” she said.
School children cross a suspension bridge over the Dhud Koshi River near Fakding village where the early warning system is installed.
Smoke emitted from a hotel in Debuche as the sun sets over Mount Everest. Recent studies show that black carbon from such smoke is causing faster retreat of the glaciers in Himalaya region.
A night view of Imja River valley from Chukum, Solukhumbu district, Nepal.