American climber dies 'suddenly' while attempting to scale Mount Makalu in Nepal

An American climber died Sunday on Mount Makalu in Nepal during a climb to raise money for a children's cancer program.

Alexander Pancoe, 39, died while settling into his sleeping bag at the mountain's second high camp after returning from an acclimatization trip at the higher camp three, according to Reuters and the company that organized the expedition, Madison Mountaineering.

Madison Mountaineering directed USA TODAY to social media posts from Monday and a tribute from on Instagram from Pancoe's wife, Nina Laski Pancoe.

"We are heartbroken by the sudden loss of our teammate and dear friend, Alex Pancoe, who passed away unexpectedly on the evening of May 4th at Camp 2 on Makalu," the company said in a Facebook post on May 5. "Alex was sharing a tent with our expedition leader and guide, Terray Sylvester. The two had just finished dinner and were settling into their sleeping bags, chatting casually, when Alex suddenly became unresponsive. Despite hours of resuscitation efforts by Terray and our team of climbers and Sherpa at Camp 2, they were unable to revive him," the company said on social media.

The company noted that earlier that day, Alex "had been in high spirits, full of energy, and was considered one of the strongest members of the team."

Pancoe's wife, Nina, wrote in her post that she and her husband shared two children together, Zephyr and Venice, and that Pancoe "died doing something you loved in a place that you loved."

According to Reuters, Nepal's tourism department said it was arranging to bring Pancoe's body to Kathmandu, the country's capital.

Nepal's Mountaineering Association did not immediately respond to a USA TODAY request for comment.

Climber battled a brain tumor and leukemia

Reuters reported that Pancoe survived a brain tumor when he was younger and had been battling chronic myeloid leukemia. His wife also wrote about his "battles of having a brain tumor and leukemia" writing "you never let that stop you."

"You lived each day to the fullest making an impact on the world around you," she wrote.

Pancoe was attempting to climb Makalu to raise funds for the pediatric blood cancer program at Lurie Children's Hospital in Chicago, expedition leader Garrett Madison told Reuters. Madison added that Pancoe had already raised $1 million to help fund clinical trials and other programs at the hospital.

Makalu is the world's fifth-highest mountain, peaking at 28,000 feet. Mount Everest, the world's tallest mountain, peaks at about 29,032 feet.