Swiss climber Uli Steck died in Nepal on Sunday in an accident near Mount Everest, Reuters reported. Steck, 40, died after falling to the foot of Mount Nuptse, a smaller peak in the area, said Mingma Sherpa of the Seven Summits Treks company that organised his expedition.

Steck is the first to perish this climbing season. “His body has been retrieved and is being brought to Kathmandu,” Sherpa told Reuters. Kamal Prasad Parajuli, an official with Nepal’s Department of Tourism, confirmed Steck’s death and said the mountaineer, who had scaled the Everest in 2012, “slipped”.

The incident took place near the route’s Camp Two, which is located at an altitude of 6,400 meters (21,000 feet), Parajuli said. It is not clear how the accident took place. He was planning to climb the the Mount Everest and nearby Mount Lhotse next month.