Supplemental oxygen strategy in high-altitude climbing

Supplemental oxygen strategy in high-altitude climbing shaped both the summit plan and the rescue risks of the Mountain Madness expedition. Oxygen was not simply carried as individual equipment: its supply was counted, divided between clients, guides, and Sherpas, and cached at planned points on the route. The May 10 strategy assumed that climbers would keep to a recommended flow rate, reach the summit within a narrow window, collect another canister at the South Summit, and descend to Camp IV before their reserves were exhausted. The plan’s precision concealed its dependence on good weather, a moving queue, accurate communication, and oxygen actually being available where and when expected.

Planning and allocation

At Base Camp, Scott Fischer and Anatoli Boukreev discussed the clients’ condition and the expedition’s oxygen situation. Boukreev asked whether oxygen would be available if he decided to climb with it; Fischer thought he was doing well and probably would not need it. Boukreev deferred the decision until summit day, asking for the same oxygen allocation as the clients. Fischer, too, had not decided whether he would climb without oxygen. He had previously summited Mount Everest without it and intended to judge his condition on the day.

The agreement between Fischer and Boukreev placed that choice within a larger rescue arrangement. If properly conditioned and acclimatized, Boukreev would guide without oxygen, while Fischer planned to provide each client with three canisters, amounting to eighteen hours of oxygen. The clients were to leave Camp IV at midnight, reach the summit, and return by 6:00 P.M., before nightfall and before their oxygen supplies ran out. Fischer had also told clients and staff that he had hired Boukreev for his ability to bring help to descending climbers, including oxygen, hot drinks, and physical assistance. The strategy therefore treated the guide’s oxygen-free ascent not as a substitute for client supplies, but as part of a rescue capacity intended to be used if the schedule failed.

The stock at Camp IV was limited. The Mountain Madness team had sixty-two canisters: nine heavier Zvesda bottles and fifty-three lighter Poisk bottles. The Zvesdas were reserved for sleeping before the climb, while the Poisk supply was designated for May 10. Only 51 percent by volume of the oxygen purchased from Henry Todd was on hand for the summit bid; most of the rest had already been consumed, especially by Pete Schoening and Ngawang Topche Sherpa, with a small amount retained at Base Camp for medical emergencies.

Allocation among the climbing party made the remaining margin explicit. Five of the six climbing Sherpas planned to use oxygen; Lopsang Jangbu Sherpa climbed without it but carried one canister for emergencies. Each of the other five Sherpas carried two bottles for personal use and two more for clients and guides, so the Sherpas took twenty-one bottles uphill. The six clients, Fischer, and Neal Beidleman carried two bottles each, while Boukreev carried one, bringing the guides’ and clients’ total to seventeen. Together the climbers carried thirty-eight Poisk canisters, leaving fifteen full Poisk bottles at Camp IV, in addition to whatever remained of the Zvesdas used overnight.

The calculations and their assumptions

Fischer’s plan drew in part on advice from oxygen supplier Henry Todd. At Todd’s recommended flow of two to two and a half liters per minute, each Poisk canister was estimated to last six hours. Two bottles would therefore provide twelve hours: enough, on paper, to climb from Camp IV to the summit and descend to the South Summit, where a third bottle was to be cached for the return. A midnight departure, favorable weather, and an uncomplicated ascent could put the climbers on the summit in ten to eleven hours, with one or two hours of oxygen remaining. From there, the descent to the South Summit was expected to take between forty-five minutes and an hour; the third bottle would then provide another six hours, enough for the return to Camp IV if the plan worked as anticipated.

That arithmetic allowed little room for delay. The fifteen full Poisk canisters left at Camp IV were not enough to support an overnight stay followed by a second summit attempt on May 11. The expedition’s margin was effectively one day: May 10 or no second bid. Charlotte Fox and Tim Madsen had already been told the governing phrase, “one shot, no more.” The oxygen strategy thus coupled supply limits to schedule pressure. A late start, slow progress, or a bottleneck could consume not just time but the reserve required for descent.

The plan also depended on the third bottles reaching the South Summit. By 10:30 A.M., climbers from the Fischer and Rob Hall teams were spread between the Balcony and just below the South Summit, mixed with Taiwanese climbers. If they had followed Todd’s recommended flow rate, many were on their second bottle and had only one to two hours of oxygen left. Their third and last bottles had not yet arrived at the cache; the Sherpas carrying them were still strung out along the route. The figures that had looked adequate under a smooth ascent became precarious amid the queue.

Bottlenecks, caches, and unexpected shortages

At the South Summit, Neal Beidleman and Martin Adams waited while climbers jammed the fixed ropes below them. Hall’s slower clients were among those ahead of the Mountain Madness group, and the Taiwanese climbers further impeded movement. Some climbers were already considering turning back as the delay threatened the one-o’clock turnaround time remembered by Lou Kasischke and others. The delay mattered directly to oxygen: the planned cache could not extend the climb if its carriers had not yet reached it.

The South Summit cache was supposed to hold ten bottles for Fischer’s team. Six were assigned to clients and one each to Beidleman and Fischer for the descent; the remaining two were presumed to be backup bottles Boukreev had requested and Fischer had agreed to place there. In practice, the group found less oxygen than expected. Beidleman recalled one full or nearly full bottle and several partly used ones; he believed the full bottle went to Lene Gammelgaard. He took a partly full canister, but it is unclear whether anyone else took another. Charlotte Fox and Martin Adams later said they had not taken additional oxygen. Martin Adams found no bottle marked for him and continued down.

The available oxygen also failed individual climbers at critical moments. Jon Krakauer, found slumped on the descent near the South Summit, had used the last of his canister. Mike Groom gave him his own bottle; Krakauer then reached the South Summit and took another from the cache maintained by Hall’s Sherpas. The episode shows the cache system working through an improvised transfer between climbers, but it also shows how survival could depend on a bottle’s presence, its location, and another person’s willingness to surrender it.

Oxygen and rescue under deteriorating conditions

When Boukreev returned to Camp IV, he understood that the Mountain Madness clients who had not yet appeared would soon be out of oxygen. Around 6:00 P.M. he prepared to go back up, carrying three canisters, a mask, and a regulator. The clouds then descended on the South Col, and wind-driven snow struck at an estimated forty to fifty miles per hour. Boukreev began using oxygen when he judged his reserves might not be enough for the search. Fogging glasses and the poor visibility made the route difficult to find; he eventually removed his mask to recover what little visibility he could.

The rescue effort was also constrained by communication. Radio messages between Dr. Ingrid Hunt at Base Camp and Fischer and Lopsang on the mountain were relayed through several intermediaries, including Ngima at Base Camp, Gyalzen at Camp II, and Pemba at Camp IV. Hunt believed she was not receiving accurate or complete information, and the connection with Pemba was sporadic. Meanwhile, Pemba did not tell Boukreev about the reported radio contact concerning whether oxygen should be carried uphill, and no one informed him that an emergency might be developing above the Hillary Step. Oxygen could be an explicit resource in the rescue plan, but communication failures obstructed decisions about where it was needed.

Significance and limits of the strategy

The oxygen plan depended on multiple systems working together: the supplier’s estimates, the number and condition of bottles, the movement of climbers and Sherpas, fixed ropes, caches, weather, and radio communication. The failure to fix ropes in advance, the resulting congestion, the late arrival of the oxygen carriers, and the small remaining reserve were not interchangeable problems, but their effects accumulated. A queue consumed time while bottles continued to empty; a cache that existed in the plan could not help climbers who reached it late or found it depleted.

The book does not identify a single cause for Scott Fischer’s death. It presents his worsening health, apparently compounded by lack of oxygen, the time and place where he was stricken, poor communications, the weather, and the condition and abilities of potential rescuers as interacting factors. That account makes the oxygen strategy significant not as a self-sufficient technical solution, but as a fragile arrangement whose safety depended on assumptions that the mountain’s actual conditions could overturn.