Rebecca Valette emailed us here at Base Camp with several questions regarding climbing route features, and I decided that if she had questions so did a lot of other followers on the website. We have sent in with this dispatch and batch of photos two photos: One of a sketch of the South Col Route and one photo of a map with the route features and camps drawn in. Many people now have a copy of the National Geographic 50th anniversary map, which I have not seen but is probably very accurate as well as a work of art. Other maps, including National Geographic maps (formerly Trails Illustrated) show some features including Base Camp in incorrect locations with incorrect routes printed on the map. Many maps available in Nepal have used this data and so are incorrect also.
And now a word about elevation values: A very large and expensive surveying-quality differential GPS would be quite accurate over time in determining correct altitudes, but normal outdoor-quality GPS is not very accurate for altitude readings. That plus the fact that most maps are not based upon data as accurate as it could be in this part of the world means that there will be variations in altitude values if different sources are consulted. This can often be plus or minus several hundred feet, so keep in mind that altitudes listed below are approximate.
Base Camp is located at the extreme north end of the bend in the Khumbu Glacier below Lingtren and Khumbutse at an elevation of just over 5,350 meters (aprox. 17,600 feet). It is on actively moving glacier ice covered by rock debris called ablation or surface moraine. A moraine is the ground up debris consisting of everything from giant boulders to fine rock powder which a glacier leaves behind. Surface moraine is the debris which is concentrated on the surface of the ice as melting and wasting takes place.
The Base Camp site is surrounded by giant overhanging ice cliffs thousands of feet above which are formed when a glacier flows over a steep or vertical rock cliff below. Thus we are treated several times per day to "icefall" and ice avalanches from Lho La (La is the local word for pass), from a huge ice cliff between Lingtren and Pumori, and from numerous ice cliffs and seracs hanging off the end of the Nuptse Ridge. And this, of course, ignores the collapses and icefalls which occur every day in the Khumbu Icefall itself. A brief note: For those interested, the term "serac" in American English climbing terms differs from European usage. For us a serac is a big block or pinnacle of ice sticking up in the middle of the feature of a glacier called an icefall. In Europe, what we call an "ice cliff", a long cliff of ice not associated with an icefall, is also called a serac.
The route from Base Camp quickly enters the Khumbu Icefall, about which much has been sent in already. The route climbs about 2,000 feet to the top of the Icefall and the entrance to the Western Cwm (pronounced "coomb"). The Western Cwm is a very steep-sided ice-filled valley surrounded by the ice and rock walls of Nuptse on the south, and the icefalls and icecliffs of the West Shoulder of Everest on the north. Camp I is situated here at an elevation of about 5,975 meters (19,600 feet) just above the Icefall but amidst many large crevasses.
If you have difficulty picturing how and why an icefall forms, think of a river. When the gradient is flat, the river flows quietly. When the gradient of the river increases, the water flows faster and faster, until finally it breaks up into a white-water rapid. An icefall is simply the slower-moving glacial equivalent of a white-water rapid. In the area just upstream where the water (ice) first starts accelerating, a glacier develops a great deal of tension stress. This tends to break the glacier apart into many crevasses on the glacier's surface (around 100 to 200 feet deep, generally). It is in this tension zone at the end of the Cwm where Camp I is located, and this presents the greatest hazard on this part of the route. Most of these crevasses are hidden, covered by bridges of snow cover. Where these crevasses form, how big they are, and how strong the overlying snow-bridge is only sometimes predictable. Thus conventional mountaineering practice and common sense dictates that we rope up through areas like this. As a survivor of snow bridge failures over completely hidden crevasses over 60 feet across, I can tell you that a rope (with adequate spacing between members) provides for great peace of mind!
About half-way to Camp II, this zone of heavy crevassing is left behind, as are the ladders spanning the huge crevasses, and the rest of the route to camp is simply a slow, uphill, high-altitude plod, about which we have spoken many times.
Camp II is located on a medial moraine at about 6,500 meters (21,300 feet) on the north side of the Western Cwm. A medial moraine is a strip of morainal debris in the middle of glacier ice which marks where two glaciers come together. At the side of a glacier is a lateral moraine (like a little ridge a bulldozer blade leaves behind as it is scraping away at the earth), and when these two lateral moraines come together when the glaciers merge, we have the combination of rock debris and ice on which Camp II is located. Camp II is likewise surrounded by 360-degrees of stunning scenery. A series of icefalls to one side, the southwest face of Everest to the other, and both the Lhotse Face and the Nupse wall across with its contorted wavy lines of sedimentary rock strata.
From Camp II, another roped glacial stroll of a couple hours leads to the base of the Lhotse Face and the beginning of the fixed lines (again). The Lhotse Face is an over 5,000 foot ice and glacier face at an average angle of around 45 per cent, and mostly consisted of hard blue ice. Don't fall here! That's why there's fixed lines anchored to the mountain. Near the middle of this face at an elevation of around 7,200 meters (23,600 feet), Camp III is literally carved out of the ice. No walking around outside here without crampons on and being clipped into a fixed line!
From this no man's land, the route climbs a bit more up the face, then veers left into a climbing traverse to the other side where it crosses the "Yellow Band." A band of yellow sandstone, quite steep and strenuous to get over at about 7,400 meters (24,300 feet). After the yellow band, the way continues up snow and ice fields, and then surmounts the black rock of the Geneva Spur, a huge and very strenuous rock ridge which must be climbed directly upwards. On our summit bid, all of this terrain above Camp III will be negotiated while breathing supplemental oxygen. It's still hard!
Once the top of the Geneva Spur is attained at around 7,700 meters (25,300 feet), it is a long but gentle traverse across rocky terrain to get to our high camp, Camp IV, in the South Col at about 7,960 meters (26,100 feet). From here we can see the majority of the route of summit day itself, including the ice bulge, literally a bulge of glacier ice just above the South Col; the triangular face of Everest (made of both ice and rock); the balcony - a diagonal ledge which leads to the top of the southeast ridge at about 8,300 meters (27,300 feet) - and the South Summit of Mt. Everest at 8,749 meters (28,700 feet). The route on summit day has two cruxes: The first is the long steep mixed rock and ice section of southeast ridge just below the south summit, and the second is the Hillary Step, much shorter (about 20 feet) but steeper, harder and higher at about 8,800 meters (28,870 feet.). From there, we hope it will be a short stroll on gentle terrain to the top of the world!
Then, of course, it's time to come home.
— Willi Prittie, Alpine Ascents International Guide and MountainZone.com Correspondent