From Chhukung, the trail heads east along the valley floor beside the Imja Khola, then climbs onto the lateral moraine of the Lhotse Shar Glacier. Island Peak rises ahead, its rocky south-west ridge and summit snow slopes clearly visible. After about 2.5 to 3 hours you reach the base camp area at around 5,087 m, a sandy flat used by climbing teams. A short climb onto the moraine to the south gives the view over Imja Tsho.
Imja Tsho barely existed in aerial photographs from the 1960s; it was a few small melt ponds on the glacier surface. As the glacier thinned and retreated, the ponds merged into a lake that now stretches more than 2 km, dammed by loose moraine. Because a sudden breach could send a flood down the valley towards Dingboche and Namche, a project in 2016 cut a controlled outlet channel and lowered the water by about 3.4 m.
The lake is grey-turquoise, bordered by ice cliffs where the glacier calves into it, and the scene is quiet apart from occasional cracks of ice. Return to Chhukung the same way. This is a long day at high altitude, so carry lunch and plenty of water, and do it only when well acclimatised. For Island Peak climbers it forms part of the approach; for trekkers it is a fascinating optional day from Chhukung.
Good for
- Photographers
- Solo
- Couples
Questions travellers ask
Why is Imja Tsho important?
Imja Tsho is one of the fastest-growing glacial lakes in the Himalaya and a well-studied example of glacier retreat. Because a moraine breach could cause a flood, it was partially drained in 2016, lowering the level by about 3.4 m to reduce the risk.
How long is the walk from Chhukung to Imja Tsho?
About 2.5–3 hours each way to the Island Peak base camp area and the moraine above the lake, so 6–7 hours return with stops. The trail gains around 350–400 m and crosses rocky moraine in the last hour.
Can you swim in Imja Tsho?
No. The water is near freezing, the shores are unstable moraine and ice cliffs calve into the lake. Enjoy it from the moraine viewpoints, and keep away from the edges and ice faces.
