K2 is the second tallest mountain in the world, but it is regarded by many experienced mountaineers as the most difficult. It is part of the Karakoram range in the Himalayas along the Pakistan-China border.
Five climbers are thought to have perished along the infamous section known as the Bottleneck. As with other Himalayan climbing tragedies in recent years, crowding on the mountain played a part in the high number of casualties. 22 climbers started out to make the summit. It is reported that as they made their way back down, a serac overhanging the Bottleneck collapsed, instantly killing 3 climbers attempting the traverse and sweeping away fixed ropes across the treacherous section. 9 climbers who had not made the traverse were trapped above 8000 meters in a region of elevation known as the "Death Zone." Initially all 11 were thought to be dead. However, Pakistani helicopters rescued 2 Dutch climbers, and 2 Austrian climbers were able to down climb and find camp III. The remaining missing mountaineers are assumed to have perished while attempting the traverse without fixed ropes or to have become lost on the mountain attempting to find camp.
Commentary by Ed Viesturs and additional links: