Last year’s earthquake in Nepal is also feared to have further destabilised Lake Imja.
The military said the project to make it safe was the highest drainage project of its kind, with army personnel and Sherpas working for six months to construct an outlet to gradually release the water.
After the outlet was constructed, nearly four million cubic metres of water was released – in a process that took two months. Top Khatri, the project’s manager with the department of hydrology and meteorology, told the BBC the process would now be applied to other lakes. “It was a pilot project that we completed without any unfortunate incident and now this model will be replicated to reduce risks in other glacial lakes as well,” Mr Khatri said.
“We suffered from some level of stress and fatigue as we were working at this high altitude and extreme location,” Lt-Col Bharat Shrestha, who headed the army team, told the BBC from the Everest region.
“In the beginning, a few people had to be evacuated as they suffered from high altitude sickness but gradually we all acclimatised ourselves to this place.”
The draining of the lake is a part of a UN project to help Nepal deal with the impact of climate change. The UN provided nearly $3m in funding to lower the lake’s water levels.
Early warning systems have also been installed for communities downstream.