Kathmandu: Renowned US ski mountaineer Hilaree Nelson has gone missing on Nepal’s Manaslu mountain, on the same day that an avalanche killed a Nepali climber on the same peak, expedition organisers and officials said Tuesday. Nelson was skiing down Manaslu after having successfully summited the world’s eighth-highest mountain with her partner Jim Morrison on Monday. “She had an accident yesterday as she was descending shortly after her summit. We are trying to get clarity on what happened,” Jiban Ghimire of Shangri-La Nepal Trek, which organised the expedition, told. Two search and rescue helicopters were sent to the area, tourism department official Bigyan Koirala said. “She is believed to have slipped close to the summit. Search teams on foot may also be deployed in the accident area,” he told. On the same day, an avalanche hit between Camps 3 and 4 on the 8,163-metre (26,781-foot) mountain, killing a Nepali climber and injuring a dozen others. “Four critically injured in the incident have been airlifted to Kathmandu for treatment. Almost all others have been evacuated,” Koirala said. The death was the first confirmed casualty of the autumn climbing season in Nepal. Constant rain and snow have been a challenge for the 404 paying climbers attempting to reach the summit of Manaslu this year, and bad weather was also hampering rescue efforts. Helicopters were unable to fly Monday and Ghimire said that conditions were deteriorating again on Tuesday afternoon. Morrison safely reached base camp and was accompanying the search and rescue team, Ghimire added. The North Face, which sponsors Nelson, confirmed the climber was missing. “We are in touch with Hilaree’s family and supporting search and rescue efforts in every way we can,” the company said in an Instagram post on Tuesday. Tested my resilience Nelson, 49, has had a career spanning two decades and is described on the company’s website as “the most prolific ski mountaineer of her generation”. In 2012, she became the first woman to summit the highest mountain in the world, Everest, and its adjacent Lhotse within 24 hours. Six years later, she returned to Lhotse and made the first ski descent of the mountain, which earned her the National Geographic Adventurer of the Year award. In an Instagram post last week, Nelson said her latest climb had been deeply challenging because of “incessant rain” and dangerous conditions. “I haven’t felt as sure-footed on Manaslu as I have on past adventure into the thin atmosphere of the high Himalaya,” Nelson said in an Instagram post on Thursday. “These past weeks have tested my resilience in new ways.” Nepal is home to eight of the world’s 14 highest peaks and foreign climbers that flock to its mountains are a major source of revenue for the country. The industry was almost completely shut down due to the coronavirus pandemic in 2020, but the country reopened its peaks to mountaineers last year.