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 organizers 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 organized the expedition, told AFP.

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 AFP. 

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.

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. 

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 Covid-19 pandemic in 2020, but the country reopened its peaks to mountaineers last year.