Shelley Johannesen, 53, was killed on Monday while descending from the summit of the world's fifth-highest peak, expedition organisers said, marking the season's latest death.

David Roubinek, a 38-year-old Czech climber, and three Nepali guides have died in the Himalayas so far this season.

Johannesen, co-founder of US-based outfitter Dash Adventures, had successfully reached the 8,485-metre summit before she was struck by an avalanche at around 7,200 metres while coming down.

"She was hit by an avalanche just below Camp 3," Nabin Trital, managing director of Expedition Himalaya, told AFP.

She was climbing with a three-member team that included her partner David Ashley and two Nepali guides.

Ashley said he was "heartbroken" by her death.

"Shelley was not just an incredible person, but lived her life with no limits and chased her passions around the world," he said in a post on social media on Tuesday.

Her body was flown to a Kathmandu hospital on Monday.

Makalu, a steep pyramid-shaped mountain southeast of Everest, is considered technically challenging because of extreme weather and its remote location.

Nepal, home to eight of the world's 10 highest peaks, attracts hundreds of climbers each year during the spring and autumn climbing seasons.

Authorities have issued more than 1,000 permits this season for 30 mountains, including 72 for Makalu and a record 492 for Everest.