The South Col usually refers to the southern col between Mount Everest and Lhotse, the first and fourth highest mountains in the world. When climbers attempt to climb Everest from the southeast ridge in Nepal, their final camp (usually camp IV) is situated on the South Col at 7,920 metres (26,000 ft). The South Col is typically ravaged by high winds, leaving it free of significant snow accumulation. In a mountain range, a pass (also gap, notch, col, saddle, or bealach) is a lower point that allows easier access through the range. ... Everest is the highest mountain on Earth. ... Lhotse is the fourth highest mountain on Earth and is connected to Mount Everest via the South Col. ...

Once on the South Col, climbers have entered the death zone. Climbers typically only have a maximum of two or three days they can endure at this altitude for making summit bids. Clear weather and low winds are critical factors in deciding whether to make a summit attempt. If weather does not cooperate within these short few days, climbers are forced to descend, many all the way back down to Base Camp. Climbers rarely get a second chance to return to the South Col in a specific expedition. The death zone is a term that refers to high altitudes, encountered by mountain climbers, where the amount of oxygen present cannot sustain human life. ...

Most climbers will begin using supplemental oxygen once they reach the South Col. Altitude sickness is a significant threat at this elevation and can easily prove fatal. Altitude sickness (also: acute mountain sickness (AMS) or altitude illness) is a pathological condition that is caused by lack of adaptation to high altitudes. ...

See also North Col. The North Col refers to the pass or col connecting Mount Everest and Changtse to its North. ...