Day of Summiting - Oxygen Shortage

Summit-day oxygen shortage was a critical vulnerability in the Mountain Madness expedition’s May 10, 1996 attempt on Mount Everest: a carefully calculated supply became a narrow margin with little room for delay, equipment uncertainty, or rescue. Its consequences were not simply a matter of how many bottles the team carried. Oxygen had to be allocated among clients, guides, and Sherpas, moved to the right place, and used in a plan whose success depended on climbers returning on schedule. When the ascent and descent ran late, that chain of assumptions became a threat to the people it was meant to protect.

Planned supply and its limits

The shortage began before summit day, in the expedition’s equipment and resource planning. Martin Adams had criticized Scott Fischer’s old two-way radios as inadequate, while the oxygen inventory posed a more immediate physical limit. At Camp IV, Mountain Madness had sixty-two canisters: nine heavier Zvesda bottles and fifty-three lighter Poisk bottles. The expedition had on hand only 51 percent by volume of the oxygen it had purchased from Henry Todd. Most of the rest had already been used, especially by Pete Schoening and Ngawang Topche Sherpa; a small quantity remained at Base Camp for medical emergencies.

The two types of canister had distinct roles. The nine Zvesda bottles were reserved for sleeping on the night before the attempt. The fifty-three Poisk bottles were designated for the climb on May 10. This separation left no generous reserve at Camp IV: the supply was divided between overnight use and the summit push before the team had begun climbing.

The planned distribution relied heavily on the Sherpas. Six Sherpas were climbing, but only five intended to use oxygen; Lopsang Jangbu Sherpa planned to climb without it, carrying one bottle for emergencies. Each of the other five Sherpas carried two bottles for personal use and two additional bottles for the clients and guides. Together, the Sherpas took twenty-one bottles from Camp IV. The six climbing clients, Fischer, and Neal Beidleman each carried two bottles, while Anatoli Boukreev carried one; the guides and clients carried seventeen bottles in total. Across all climbers, thirty-eight Poisk canisters went up the mountain, leaving fifteen full Poisk bottles at Camp IV, in addition to whatever remained of the Zvesdas used overnight.

That arithmetic made the plan’s lack of reserve explicit. The remaining stock was not enough to support an overnight delay and a second summit attempt on May 11. Charlotte Fox and Tim Madsen had already been told there would be only one attempt. The expedition’s supply therefore imposed a fixed operational boundary: if the May 10 bid encountered significant complications, there was no comparable second effort waiting in reserve.

The schedule built into the oxygen plan

Fischer’s calculations were based partly on advice from oxygen supplier Henry Todd. At a recommended flow rate of two to two and a half liters per minute, Todd estimated that one Poisk canister would last six hours. Two bottles, he reasoned, would provide twelve hours—enough to climb from Camp IV to the summit and descend to the South Summit, where climbers were supposed to collect a third bottle from a cache. The planned midnight departure was expected to put the team on the summit in ten or eleven hours, leaving one or two hours of oxygen in the first two canisters. From the summit, a descent of roughly forty-five minutes to an hour to the South Summit would bring the climbers to the additional supply; with that third bottle, the plan anticipated enough oxygen to get back to Camp IV.

The calculation was conditional at every step. It assumed the weather held, the climbing proceeded without complications, the recommended flow rate was followed, and the cached bottles were accessible when needed. The cache was a crucial link, not a surplus carried by each climber from the start. On paper, the plan converted the available oxygen into a full summit-and-return schedule; in practice, the margin depended on time and coordination holding together.

The broader arrangement also shaped Boukreev’s role. He and Fischer had agreed before the expedition that Boukreev would guide without oxygen if he was properly conditioned and acclimatized. Fischer planned to provide each client with three canisters, representing eighteen hours of oxygen, and expected the clients to return by 6:00 P.M., before darkness and before their supply ran out. Fischer had hired Boukreev in part for his ability to bring descending climbers oxygen, hot drinks, and physical assistance if they needed help. In this division of labor, the clients’ bottles were their planned climbing supply; Boukreev’s reserve capacity as a rescuer was meant to respond if the schedule failed. His early descent was later explained in that context: he went down not simply because he was climbing without oxygen, but because the clients were using it and could exhaust their supply before reaching Camp IV.

Delays and uncertain coordination

The summit-day plan depended on more than oxygen. It also depended on the route being prepared in advance so that climbers would not have to wait at difficult sections. Clients from the Mountain Madness and Adventure Consultants teams understood that their Sherpas would fix the ropes between Camp IV and the summit before the clients set out. In fact, no Sherpas had departed early to do so. Lopsang later said that a member of a Montenegrin expedition that had attempted the summit on May 9 told him the ropes were already fixed. Jon Krakauer questioned this explanation, while the book also presents the possibility that Fischer and Rob Hall believed the work had been done and were exhausted and occupied with their own concerns. Whatever the explanation, the intended rope preparation had not occurred, adding delay to an ascent whose oxygen calculations allowed little slack.

The absence of a firm, communicated turnaround time further weakened the schedule. Fischer had not told his climbers to turn around at a stated altitude or hour. Instead, he had planned for Lopsang, Boukreev, and Beidleman to alternate at the front while Fischer followed behind and turned back stragglers; if a problem arose, he expected to contact Lopsang by radio. Neither Boukreev nor Beidleman had been issued a radio. A strategy that relied on recognizing and responding to trouble thus had a communications gap, just as the oxygen plan relied on accurate estimates and prompt progress.

The supply figures themselves became uncertain in later discussion. During a debriefing, Boukreev asked how many extra bottles the Sherpas had carried for members, and Lopsang answered ten. In a later exchange, Tim estimated eleven bottles available for others’ use, while Klev described the Sherpas’ bottles differently. These recollections do not settle the count; they show that, in retrospect, the reserve and distribution were not remembered with one consistent figure. That ambiguity mattered because the oxygen cache and Sherpa-carried bottles were not incidental details: they were supposed to provide the margin when a climber’s own supply ran low.

Shortage during the descent

The pressure of limited oxygen became concrete near the South Summit. Neal Beidleman recalled that Klev Schoening was testing bottles at a rock just below the summit. One bottle appeared full or nearly full, while several others had only three to five units of pressure remaining. Beidleman was close to running out himself, as were some of the clients. The recollection is explicitly uncertain—he described the details as blurred—but it records a descent in which people were checking partial bottles and deciding who could use what remained. The full bottle, he recalled, went to Lene Gammelgaard.

Beidleman said that one of his bottles ran out somewhere near or below the upper set of fixed ropes. He continued for a while without oxygen and began to stumble. He asked Tashi Sherpa to switch the hose from one bottle to the other; he was unsure whether the old bottle was removed, and remembered having only a small pressure left. He asked for the flow to be reduced to the lowest setting, which he believed was half a liter per minute, and continued descending. Oxygen shortage here was a practical sequence of depletion, improvisation, and reduced flow, not merely an inventory figure written at Camp IV.

Other climbers’ condition added urgency to the checks. At the Hillary Step, Sandy Hill Pittman struggled to identify which tangled, wind-worn cord to clip into and how to negotiate the steps. Beidleman tried to help her descend, but the cords were too tangled to rappel her down as intended, so she descended by hand with assistance. On the ridge, the group was also working with a dwindling supply: the accounts describe climbers close to or out of oxygen and a small number of partly used bottles. Such moments made the link between route delays and oxygen consumption immediate. A delay on the mountain did not only postpone arrival at camp; it ate into a finite supply needed to keep moving and to manage the descent.

Communication and emergency consequences

Oxygen could not be sent or redirected effectively without reliable communication. At Base Camp, Dr. Ingrid Hunt depended on messages passed through a chain of Sherpa radio operators between Base Camp, Camp II, and Camp IV. She later described the relaying process as indirect, with messages passed from one person to another and back again. She believed she was not receiving accurate or complete information and that reports were being improved to make the situation sound better. Communication with Pemba Sherpa was sporadic. As the emergency escalated, Hunt moved between the Mountain Madness camp and Rob Hall’s camp because Hall’s had better communications.

The timing of the reports shows how the shortage and the communication problem converged. At about 4:30 P.M., people from Hall’s camp told Hunt that a climber had collapsed above the Hillary Step and that Hall was with him; they asked for oxygen to be sent up. Hunt and the Sherpas tried to reach people on the mountain and asked Pemba whether he could go, but he said the weather was too bad and he did not want to. At 5:45 P.M., Hunt received a report that Lopsang and Fischer were below the South Summit, out of oxygen, and that Fischer was very weak. She was then unable to get further information for hours. At 10:46 P.M., a message from Pemba said that Fischer, Lopsang, Makalu Gau, three Taiwanese Sherpas, and one New Zealand Sherpa were near the South Col, flashing headlights and making noise with oxygen bottles to attract attention. Hunt, hearing that the area was in a complete whiteout, doubted whether the reported signaling could be seen.

This sequence distinguishes carrying oxygen from being able to deliver it where it was needed. The team had planned for a third canister at the South Summit, and Boukreev’s rescue role assumed he could bring aid to descending climbers. But the climbers had to reach the cache, their remaining bottles and pressure had to be understood, and messages had to travel through an unreliable chain. When Fischer and others were reported out of oxygen and weak, the distance between a bottle in an inventory and oxygen in a climber’s mask became decisive.

The book does not reduce the shortage to a single cause. It connects a constrained inventory with a plan dependent on supplier estimates, a fixed summit schedule, an uncompleted rope-fixing expectation, uncertain bottle counts, and communications that delayed or clouded the response. Each problem narrowed the options available to the others. Oxygen depletion therefore figures both as a bodily danger and as a measure of how little redundancy the expedition had built into its attempt: once the schedule and the supply ceased to match, neither the remaining bottles nor the rescue plan could guarantee a safe return.