Editing Mount Everest (section)

===Routes===

[[File:STS058-101-12 2.JPG|thumb|Overview South Col route and North Col/Ridge route]]
Mount Everest has two main climbing routes, the Southeast Ridge from [[Nepal]] and the North Ridge from [[Tibet]], as well as many other less frequently climbed routes.<ref name=evhist>{{cite web|url=http://www.everesthistory.com/routes.htm |title=Ascent Routes on Everest |publisher=EverestHistory.com |access-date=21 January 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080115161830/http://www.everesthistory.com/routes.htm |archive-date=15 January 2008}}</ref> Of the two main routes, the Southeast Ridge is technically easier and more frequently used. It was the route used by [[Edmund Hillary]] and [[Tenzing Norgay]] in 1953 and the first recognised of 15 routes to the top by 1996.<ref name=evhist/> This was, however, a route decision dictated more by politics than by design, as the Chinese border was closed to the western world in the 1950s, after [[Annexation of Tibet by the People's Republic of China]].<ref name=ngetl>{{cite web|url=https://www.nationalgeographic.com/news/2003/04/0401_030401_everesttimeline.html| title=Everest Time Line: 80 Years of Triumph and Tragedy|publisher=National Geographic Society|last=Thompson|first=Kalee|date=2 April 2003|access-date=28 March 2008|archive-url=https://web.archive.org/web/20090325032404/http://news.nationalgeographic.com/news/2003/04/0401_030401_everesttimeline.html|archive-date=25 March 2009}}</ref>

Most attempts are made during May, before the summer [[monsoon]] season. As the monsoon season approaches, the [[jet stream]] shifts northward, thereby reducing the average wind speeds high on the mountain.<ref name=nytimes>{{cite news|url=https://query.nytimes.com/gst/fullpage.html?res=9E01EFDD1E38F93AA25756C0A961958260|title=Climbing Mount Everest|work=The New York Times|date=19 May 1997|access-date=24 October 2008|archive-date=6 February 2009|archive-url=https://web.archive.org/web/20090206223111/http://query.nytimes.com/gst/fullpage.html?res=9E01EFDD1E38F93AA25756C0A961958260|url-status=live}}</ref><ref name=te03>{{cite web|url=http://www.teameverest03.org/everest_info/index.html|title=Mt. Everest Information|author=Team Everest 03|access-date=24 October 2008|archive-date=11 February 2010|archive-url=https://web.archive.org/web/20100211140355/http://www.teameverest03.org/everest_info/index.html|url-status=dead}}</ref> While attempts are sometimes made in September and October, after the monsoons, when the jet stream is again temporarily pushed northward, the additional snow deposited by the monsoons and the less stable weather patterns at the monsoons' tail end makes climbing extremely difficult.

====Southeast Ridge====
The ascent via the Southeast Ridge begins with a trek to [[Everest Base Camp|Base Camp]] at {{convert|5380|m|ft|-2|abbr=on}} on the south side of Everest, in Nepal. Expeditions usually fly into [[Lukla]] (2,860&nbsp;m) from [[Kathmandu]] and pass through [[Namche Bazaar]]. Climbers then hike to Base Camp, which usually takes six to eight days, allowing for proper altitude acclimatisation in order to prevent [[altitude sickness]].<ref name=Acclimatization>{{cite journal |author1=Muza, SR |author2=Fulco, CS |author3=Cymerman, A |title=Altitude Acclimatization Guide |journal=US Army Research Inst. Of Environmental Medicine Thermal and Mountain Medicine Division Technical Report |issue=USARIEM–TN–04–05 |year=2004 |url=http://archive.rubicon-foundation.org/7616 |access-date=5 March 2009 |archive-date=23 April 2009 |archive-url=https://web.archive.org/web/20090423042451/http://archive.rubicon-foundation.org/7616 |url-status=usurped}}</ref> Climbing equipment and supplies are carried by [[yak]]s, [[dzo]]pkyos (yak-cow hybrids), and human [[porter (carrier)|porters]] to Base Camp on the [[Khumbu Glacier]]. When Hillary and Tenzing climbed Everest in 1953, the British expedition they were part of (comprising over 400 climbers, porters, and Sherpas at that point) started from the [[Kathmandu Valley]], as there were no roads further east at that time.

Climbers spend a couple of weeks in Base Camp, acclimatising to the altitude. During that time, [[Sherpa (people)|Sherpas]] and some expedition climbers set up ropes and ladders in the treacherous [[Khumbu Icefall]].

[[Serac]]s, [[crevasse]]s, and shifting blocks of ice make the icefall one of the most dangerous sections of the route. Many climbers and Sherpas have been killed in this section. To reduce the hazard, climbers usually begin their ascent well before dawn, when the freezing temperatures glue ice blocks in place.

Above the icefall is Camp I at {{convert|6065|m|ft|-1}}.
[[File:Inside Khumbu-Icefall.jpg|thumb|Climber traversing Khumbu Icefall]]
From Camp I, climbers make their way up the [[Western Cwm]] to the base of the [[Lhotse]] Face, where Camp II or Advanced Base Camp (ABC) is established at {{convert|6500|m|ft|-2|abbr=on}}. The Western Cwm is a flat, gently rising glacial valley, marked by huge lateral crevasses in the centre, which prevent direct access to the upper reaches of the Cwm. Climbers are forced to cross on the far right, near the base of [[Nuptse]], to a small passageway known as the "Nuptse corner". The Western Cwm is also called the "Valley of Silence" as the topography of the area generally cuts off wind from the climbing route. The [[high altitude]] and a clear, windless day can make the Western Cwm unbearably hot for climbers.<ref name=nova-climb>{{cite web|url=https://www.pbs.org/wgbh/nova/everest/climb/waytosummitsou.html|title=The Way to the Summit|publisher=Public Broadcasting Corporation|website=NOVA Online|year=2000|access-date=28 March 2008|archive-date=30 September 2011|archive-url=https://web.archive.org/web/20110930100116/http://www.pbs.org/wgbh/nova/everest/climb/waytosummitsou.html|url-status=live}}</ref>

From Camp II, climbers ascend the Lhotse Face on [[fixed rope]]s, up to Camp III, located on a small ledge at {{convert|7470|m|ft|-2|abbr=on}}. From there, it is another 500 metres to Camp IV on the [[South Col]] at {{convert|7920|m|ft|-2|abbr=on}}.

From Camp III to Camp IV, climbers are faced with two additional challenges: the [[Geneva Spur]] and the [[Yellow Band]]. The Geneva Spur is an anvil-shaped rib of black rock named by the [[1952 Swiss Mount Everest Expedition|1952 Swiss expedition]]. Fixed ropes assist climbers in [[scrambling]] over this snow-covered rock band. The Yellow Band is a section of interlayered [[marble]], [[phyllite]], and [[schist|semischist]], which also requires about 100 metres of rope for traversing it.<ref name=nova-climb/>

On the [[South Col]], climbers enter the [[death zone]]. Climbers making summit bids typically can endure no more than two or three days at this altitude. If the weather is not clear with low winds during these short few days, climbers are forced to descend, many all the way back down to Base Camp.

From Camp IV, climbers begin their summit push around midnight, with hopes of reaching the summit (still another 1,000 metres above) within 10 to 12 hours. Climbers first reach "The Balcony" at {{convert|8400|m|ft|-2|abbr=on}}, a small platform where they can rest and gaze at peaks to the south and east in the early light of dawn. Continuing up the ridge, climbers are then faced with a series of imposing rock steps which usually forces them to the east into the waist-deep snow, a serious [[avalanche]] hazard. At {{convert|8750|m|ft|-2|abbr=on}}, a small table-sized dome of ice and snow marks the [[South Summit (Everest)|South Summit]].<ref name=nova-climb/>

From the South Summit, climbers follow the knife-edge Southeast Ridge along what is known as the "Cornice traverse", where snow clings to intermittent rock. This is the most exposed section of the climb, and a misstep to the left would send one {{convert|2400|m|ft|abbr=on}} down the Southwest Face, while to the immediate right is the {{convert|3050|m|ft|abbr=on}} [[Kangshung Face]]. At the end of this traverse is an imposing {{convert|12|m|ft|abbr=on}} rock wall, the [[Hillary Step]], at {{convert|8790|m|ft|-1|abbr=on}}.<ref>{{Cite book|url=https://books.google.com/books?id=qJjIBFOMsQsC&q=hillary+step&pg=PT111|title=On Top of World: My Everest Adventure|last=Vajpai|first=Arjun|date=2010|publisher=Penguin UK|isbn=978-81-8475-304-2|access-date=10 November 2020|archive-date=5 October 2024|archive-url=https://web.archive.org/web/20241005161248/https://books.google.com/books?id=qJjIBFOMsQsC&q=hillary+step&pg=PT111#v=snippet&q=hillary%20step&f=false|url-status=live}}</ref>

Hillary and Tenzing were the first climbers to ascend this step, and they did so using primitive ice climbing equipment and ropes. Nowadays, climbers ascend this step using fixed ropes previously set up by Sherpas. Once above the step, it is a comparatively easy climb to the top on moderately angled snow slopes—though the [[exposure (heights)|exposure]] on the ridge is extreme, especially while traversing large cornices of snow. With increasing numbers of people climbing the mountain in recent{{When|date=May 2021}} years, the Step has frequently become a bottleneck, with climbers forced to wait significant amounts of time for their turn on the ropes, leading to problems in getting climbers efficiently up and down the mountain.{{Citation needed|date=May 2021}}

After the Hillary Step, climbers also must traverse a loose and rocky section that has a large entanglement of fixed ropes that can be troublesome in bad weather. Climbers typically spend less than half an hour at the summit to allow time to descend to Camp IV before darkness sets in, to avoid serious problems with afternoon weather, or because supplemental oxygen tanks run out.

====North Ridge route====
{{see also|Three Steps}}
[[File:Mount Everest North Face.jpg|thumb|Mount Everest North Face from [[Rongbuk Monastery|Rongbuk]] in Tibet]]
The North Ridge route begins from the north side of Everest, in [[Tibet]]. Expeditions trek to the [[Rongbuk Glacier]], setting up base camp at {{convert|5180|m|ft|-1|abbr=on}} on a gravel plain just below the glacier. To reach Camp II, climbers ascend the medial moraine of the east Rongbuk Glacier up to the base of [[Changtse]], at around {{convert|6100|m|ft|-2|abbr=on}}. Camp III (ABC{{snd}}Advanced Base Camp) is situated below the [[North Col]] at {{convert|6500|m|ft|abbr=on}}. To reach Camp IV on the North Col, climbers ascend the glacier to the foot of the col where fixed ropes are used to reach the North Col at {{convert|7010|m|ft|-2|abbr=on}}. From the North Col, climbers ascend the rocky North Ridge to set up Camp V at around {{convert|7775|m|ft|-2|abbr=on}}. The route crosses the North Face in a diagonal climb to the base of the Yellow Band, reaching the site of Camp VI at {{convert|8230|m|ft|-2|abbr=on}}. From Camp VI, climbers make their final summit push.

Climbers face a treacherous traverse from the base of the First Step: ascending from {{convert|8501|to|8534|m|ft|-1|abbr=on}}, to the crux of the climb, the Second Step, ascending from {{convert|8577|to|8626|m|ft|-1|abbr=on}}. (The Second Step includes a climbing aid called the "Chinese ladder", a metal ladder placed semi-permanently in 1975 by a party of Chinese climbers.<ref>{{cite web|url=http://www.affimer.org/hemmleb7.html|publisher=Affirmer.org |title=Chinese ladder|access-date=16 January 2014|archive-date=16 January 2016|archive-url=https://web.archive.org/web/20160116101043/http://www.affimer.org/hemmleb7.html|url-status=dead}}</ref> It has been almost continuously in place since, and ladders have been used by virtually all climbers on the route.) Once above the Second Step the inconsequential Third Step is clambered over, ascending from {{convert|8690|to|8800|m|ft|-1|abbr=on}}. Once above these steps, the summit pyramid is climbed by a snow slope of 50 degrees, to the final summit ridge along which the top is reached.<ref name=NOVA_wtsn>{{cite web|url=https://www.pbs.org/wgbh/nova/everest/climb/waytosummitnor.html|title=The Way to the Summit (North)|publisher=Public Broadcasting Corporation|website=NOVA Online|year=2000|access-date=28 March 2008|archive-date=20 September 2011|archive-url=https://web.archive.org/web/20110920124802/http://www.pbs.org/wgbh/nova/everest/climb/waytosummitnor.html|url-status=live}}</ref>