Henize acclimatized at Kathmandu, Nepal, followed by acclimatization at expedition base camp in China. Henize, with three members of High Adventure BVI, began the hike on October 4, 1993. On their way to advanced base camp, Henize reported breathing problems. They were at 22,000 feet. Treatments with oxygen failed, and they returned to base camp. On October 5, Henize died in his sleep. The cause of death was determined to be high altitude pulmonary edema (HAPE). Henize, aged 66, was buried near the Changtse Glacier. He was survived by his wife, Caroline, and four children.