The famed Khumbu Icefall transitions the glacier from the accumulation zone to the ablation zone, the ablation zone being where the melting happens. Base camp for the climbing expeditions sits on a debris-covered section of the glacier, below the Khumbu Icefall. The debris cover is brought down by avalanches and uncovered at the surface due to melting.
While Mount Everest is famous, known as the top of the world because of its size – it stands at an astonishing 29,029 feet above sea level – it is also notorious for its harsh climbing conditions and the treacherous weather that faces climbers. Temperatures can fall below -100 degrees Fahrenheit or even colder, and the winds gust with the strength of a category 3 hurricane, at 118 miles per hour or more.
Then there is the altitude: as you progress higher up Mount Everest, the amount of oxygen needed to sustain life decreases rapidly until you reach the summit, where there is only a third of the level of oxygen needed to sustain human life. You would think that any of these factors would present the most difficult challenge to a climber, but oddly enough, most climbers do not perceive them to be the most dangerous that they face.
In fact, most climbers tend to agree that the hardest part of the mountain to climb is actually the Khumbu Icefall, just above base camp. The icefall is one of the most treacherous stages of the South Col route that takes you to the summit of Mount Everest.
The Khumbu Icefall is the point in the glacier where it begins to melt. Because of this, it is like trying to climb over a moving sea of ice at times. The entire glacier is immensely unstable, and the average climber can expect to be in this extraordinarily dangerous area for between four and six hours before they ascend 2,000 feet to the top of the glacier where Camp One is located.
The entire Khumbu Icefall requires clipping and unclipping from fixed lines (ropes attached to the mountain with pickets buried in the snow) and crossing dark, bottomless crevasses on nothing more then a regular old garden ladder – all while wearing crampons on your feet.
With the glacier moving constantly, crevasses open up with no warning at all and huge blocks of ice, up to the size of a house, can fall from above. Blocks of ice shift; large pieces can crack off and tumble down through the icefall, forming a maze of pieces that the climber must work quickly to skillfully to navigate.
Every second spent navigating through the icefall is a second that you are risking your life. Unfortunately, mishaps can and do happen on the icefall. Sadly, these frequently occur when climbers fall into crevasses or are hit by falling blocks of ice.