Calcutta, May 22: Uncertainty over the fate of mountaineer Chanda Gayen, along with Pemba Sherpa and Dawa Wangchu Sherpa, looms large with the rescue party returning empty handed today morning.

Last heard, Tashi Sherpa, who was leading Chanda in her expedition to Yalung Kang (8,505m), also called Kanchenjunga West, reached the base camp (5,100m).

“We sent a helicopter today morning. But, we had to call off the operation because of inclement weather,” said Mingma Sherpa, managing director of Seven Summit Treks that had organised the expedition.

Bengal Everester Chanda, 32, successfully climbed Kanchenjunga Main (8,598ft) on Sunday around 9.30am. But, she has been missing after an avalanche hit her above the summit camp of over 8,000 metres, while she was trying to ascend Yalung Kang around 3pm on Tuesday.

The main feature of Yalung Kang is a large sloping plateau, commonly known as Great Shelf, where the mishap had occurred. A hanging glacier covers the place, and the route is almost entirely on snow and one icefall, sources said.

“Inclement weather has become an impediment in our search operation. Though we had sent the helicopter twice, the rescue members could not locate any of the missing mountaineers,” said Mingma.

“A helicopter generally can’t fly above 6,000 metres. In case of a rescue mission on a high altitude, we send special helicopters. But, in most of the cases, it can’t land due to the absence of a helipad. The rescue members are dropped on a surface once they locate the subjects (the trapped or missing mountaineers are called subjects in a rescue mission) and then reach them on foot,” said the veteran sherpa.