喬戈里峰

There are a number of routes on K2, of somewhat different character, but they all share some key difficulties: First is the extreme high altitude and resulting lack of oxygen: in fact there is only one third as much oxygen available to a climber on the summit of K2 as there is at sea level. Second is the propensity of the mountain to extreme storms of several days' duration, which have resulted in many of the deaths on the peak. Third is the steep, exposed, and committing nature of all routes on the mountain, which makes retreat more difficult, especially during a storm.

The standard route of ascent, used far more than any other route, is the Abruzzi Spur, first attempted by Luigi Amedeo, Duke of the Abruzzi in 1909 (see the history above). This is the southeast ridge of the peak, rising above the Godwin Austen Glacier. The spur proper begins at an altitude of 5,400 m, where Advanced Base Camp is usually placed. The route follows an alternating series of rock ribs, snow/ice fields, and some technical rock climbing on two famous features, "House's Chimney" and the "Black Pyramid." Above the Black Pyramid, dangerously exposed and difficult to navigate slopes lead to the easily visible "Shoulder," and thence to the summit. The last major obstacle is a narrow couloir known as the "Bottleneck," which places climbers dangerously close to a wall of seracs which form an ice cliff to the east of the summit. (It was partly due to the collapse of one of these seracs around 2001 that no climbers summited the peak in 2002 and 2003.)

Almost opposite from the Abruzzi Spur is the North Ridge, which ascends the Chinese side of the peak. It is rarely climbed, partly due to very difficult access, involving crossing the Shaksgam River, which is a hazardous undertaking.[12]. In contrast to the crowds of climbers and trekkers at the Abruzzi basecamp, usually at most two teams are encamped below the North Ridge. This route, more technically difficult than the Abruzzi, ascends a long, steep, primarily rock ridge to high on the mountain (Camp IV, the "Eagle's Nest", 7,900 m), and then crosses a dangerously slide-prone hanging glacier by a leftward climbing traverse, to reach a snow couloir which accesses the summit.

Besides the original Japanese ascent (see the History section), a notable ascent of the North Ridge was the one in 1990 by Greg Child, Greg Mortimer, and Steve Swenson, which was done alpine-style (though using some fixed ropes already put in place by previous teams).