On May 14, extreme climber Ueli Steck had a new message in his inbox. "The window from the 16th to the 19th appears to be stable," the meteorologists from Switzerland wrote. Stable means little wind, good visibility and no snowfall. Fourteen minutes later, Steck replied: "Great, I'll get going right away." Steck, who has already climbed several 8,000ers, was one of the first to begin the climb to the summit. Word quickly spread through base camp. Talking to Himself in the Death Zone On May 15, starting at 3 a.m., more than 300 climbers set out for the summit. They included Irmak and the two Germans, Schaaf and Thelen. They crossed the Khumbu Icefall. Like a giant procession, the climbers worked their way up the mountain, from Camp 2 at 6,400 meters to Camp 3 at 7,200 meters, and on to Camp 4, the last before the summit. The march kept coming to a standstill at the Yellow Band, a steep passage on Lhotse Face, above 7,500 meters. There were simply too many people climbing that day, leading to congestion and friction among the climbers. At times they had to wait more than 30 minutes for the climb to continue. Passing other climbers was almost impossible, because it would have cost too much energy. Besides, it's dangerous for climbers to disconnect themselves from the fixed rope. The average gradient along the wall of glacial ice is 35 degrees.
The march from the base camp to Camp 4, at about 8,000 meters, takes three days. Sherpas had already stocked the camp with oxygen bottles, where they sat waiting for climbers ready to take on the last stage to the summit. Almost all climbers at that altitude wear oxygen masks, which draw in ambient air and mix it with oxygen from the bottles, making it easier to breathe.
Normally, climbers reach Camp 4 at about noon. They rest a few hours, and then they leave that evening so that they'll be at the summit in the morning. But this time, the plan didn't work. Because of the congestion, everyone arrived late at Camp 4.
Irmak stumbled into the camp at about 3 p.m., while Schaaf didn't arrive until about 4:30. He went to his tent to lie down, while his Sherpas made him some hot oatmeal and tea. Although he knew that he would have only four hours to recover, Schaaf decided to leave for the summit that evening. Thelen reached Camp 4 at about 6 p.m. Exhausted, he radioed the manager of his agency at the basis, saying: "I don't have any energy left. I'll wait until tomorrow to continue."
Mental Capacity of a Small Child
In the death zone, barometric pressure is only about a third of what it is at sea level, meaning that there is less pressure to push oxygen into the lungs. Breathing is difficult and climbers can only move at very slow speeds, even though their hearts are racing. So little oxygen reaches the brain that climbers revert to the mental capacity of a small child. Their minds become dull and their ability to perceive their environment is limited.
Oxygen deprivation causes brain cells die off and the blood to thicken. There are two forms of altitude sickness that are life-threatening: pulmonary edema, in which water accumulates in the lungs, and brain edema, in which fluid collects in the skull. Within a few hours, a brain edema can trigger swelling of the head that puts the mountain climber into a coma. People who develop altitude sickness in the death zone have to descend as quickly as possible.