Mountaineering

Mountaineering or mountain climbing is the sport, hobby or profession of hiking, skiing, and climbing mountains. While mountaineering began as attempts to reach the highest point of unclimbed mountains it has branched into specializations that address different aspects of the mountain and consists of three areas: rock-craft, snow-craft and skiing, depending on whether the route chosen is over rock, snow or ice. All require experience, athletic ability, and technical knowledge to maintain safety.[2]

The UIAA or Union Internationale des Associations d'Alpinisme is the world governing body in mountaineering and climbing, addressing issues like access, medical, mountain protection, safety, youth and ice climbing.[3]

Contents

Technique

Snow

Compacted snow conditions allow mountaineers to progress on foot. Frequently crampons are required to travel efficiently over snow and ice. Crampons have 8-14 spikes and are attached to a mountaineer's boots. They are used on hard snow (neve) and ice to provide additional traction. Using various techniques from alpine skiing and mountaineering to ascend/descend a mountain is a form of the sport by itself, called ski mountaineering. Ascending and descending a snow slope safely requires the use of an ice axe and many different footwork techniques that have been developed over the past century, mainly in Europe. The progression of footwork from the lowest angle slopes to the steepest terrain is first to splay the feet to a rising traverse, to kicking steps, to front pointing the crampons. The progression of ice axe technique from the lowest angle slopes to the steepest terrain is to use the ice axe first as a walking stick, then a stake, then to use the front pick as a dagger below the shoulders or above, and finally to swing the pick into the slope over the head. These various techniques may involve questions of differing ice-axe design depending on terrain, and even whether a mountaineer uses one or two ice axes. Anchors for the rope in snow are sometimes unreliable, and include snow stakes, called pickets, deadman devices called flukes which are fashioned from aluminium, or devised from buried objects that might include an ice axe, skis, rocks or other objects. Bollards, which are simply carved out of consolidated snow or ice, also sometimes serve as anchors.

Glaciers

When travelling over glaciers, crevasses pose a grave danger. These giant cracks in the ice are not always visible as snow can be blown and freeze over the top to make a snowbridge. At times snowbridges can be as thin as a few inches. Climbers use a system of ropes to protect themselves from such hazards. Basic gear for glacier travel includes crampons and ice axes. Teams of two to five climbers tie into a rope equally spaced. If a climber begins to fall the other members of the team perform a self-arrest to stop the fall. The other members of the team enact a crevasse rescue to pull the fallen climber from the crevasse.

Ice

Multiple methods are used to safely travel over ice. If the terrain is steep but not vertical, then the lead climber can place ice screws in the ice and attach the rope for protection. Each climber on the team must clip past the anchor, and the last climber picks up the anchor itself. Occasionally, slinged icicles or bollards are also used. This allows for safety should the entire team be taken off their feet. This technique is known as Simul-climbing and is sometimes also used on steep snow and easy rock.

If the terrain becomes too steep, standard ice climbing techniques are used in which each climber is belayed, moving one at a time.

Shelter

Climbers use a few different forms of shelter depending on the situation and conditions. Shelter is a very important aspect of safety for the climber as the weather in the mountains may be very unpredictable. Tall mountains may require many days of camping on the mountain.

Base Camp

The "Base Camp" of a mountain is an area used for staging an attempt at the summit. Base camps are positioned to be safe from the harsher conditions above. There are base camps on many popular or dangerous mountains. Where the summit cannot be reached from base camp in a single day, a mountain will have additional camps above base camp. For example, the southeast ridge route on Mount Everest has Base Camp plus (normally) camps I through IV.

Hut

The European alpine regions, in particular, have a network of mountain huts (called "refuges" in France, "rifugi" in Italy, "cabanes" in Switzerland, "Hütten" in Germany and Austria, "koča" in Slovenia, "refugios" in Spain and "hytte" in Norway). Such huts exist at many different heights, including in the high mountains themselves – in extremely remote areas, more rudimentary shelters may exist. The mountain huts are of varying size and quality, but each is typically centred on a communal dining room and have dormitories equipped with mattresses, blankets or duvets, and pillows; guests are expected to bring and to use their own sleeping bag liner. The facilities are usually rudimentary but, given their locations, huts offer vital shelter, make routes more widely accessible (by allowing journeys to be broken and reducing the weight of equipment needing to be carried), and offer good value. In Europe, all huts are staffed during the summer (mid-June to mid-September) and some are staffed in the spring (mid-March to mid-May). Elsewhere, huts may also be open in the fall. Huts also may have a part that is always open, but unmanned, a so-called winter hut. When open and manned, the huts are generally run by full-time employees, but some are staffed on a voluntary basis by members of Alpine clubs (such as Swiss Alpine Club and Club alpin français) or in North America by Alpine Club of Canada. The manager of the hut, termed a guardian or warden in Europe, will usually also sell refreshments and meals; both to those visiting only for the day and to those staying overnight. The offering is surprisingly wide; given that most supplies, often including fresh water, must be flown in by helicopter, and may include glucose-based snacks (such as Mars and Snickers bars) on which climbers and walkers wish to stock up, cakes and pastries made at the hut, a variety of hot and cold drinks (including beer and wine), and high carbohydrate dinners in the evenings. Not all huts offer a catered service, though, and visitors may need to provide for themselves. Some huts offer facilities for both, enabling visitors wishing to keep costs down to bring their own food and cooking equipment and to cater using the facilities provided. Booking for overnight stays at huts is deemed obligatory, and in many cases is essential as some popular huts; even with more than 100 bed spaces may be full during good weather and at weekends. Once made, the cancellation of a reservation is advised as a matter of courtesy – and, indeed, potentially of safety, as many huts keep a record of where climbers and walkers state they planned to walk to next. Most huts may be contacted by telephone and most take credit cards as a means of payment.

Bivouac (bivy or bivvy)

In the mountaineering context, a bivouac or "biv(v)y" is a makeshift resting or sleeping arrangement in which the climber has less than the full complement of shelter, food and equipment that would normally be present at a conventional campsite. This may involve simply getting a sleeping bag and Bivouac sack/bivvy bag and lying down to sleep. Typically bivvy bags are made from breathable waterproof membranes which stop the user sweating too much, which in sub zero environments can be very dangerous. Many times small partially sheltered areas such as a bergschrund, cracks in rocks or a trench dug in the snow are used to provide additional shelter from wind. These techniques were originally used only in emergency; however some climbers steadfastly committed to alpine style climbing specifically plan for bivouacs in order to save the weight of a tent when suitable snow conditions or time is unavailable for construction of a snow cave. The principal hazard associated with bivouacs is the greater level of exposure to cold and the elements.

Tent

Tents are the most common form of shelter used on the mountain. These may vary from simple tarps to much heavier designs intended to withstand harsh mountain conditions. In exposed positions, windbreaks of snow or rock may be required to shelter the tent. One of the downsides to tenting is that high winds and snow loads can be dangerous and may ultimately lead to the tent's failure and collapse. In addition, the constant flapping of the tent fabric can hinder sleep and raise doubts about the security of the shelter. When choosing a tent, alpinists tend to rely on specialised mountaineering tents that are specifically designed for high winds and moderate to heavy snow loads. Tent stakes can be buried in the snow ("deadman") for extra security.

Snow cave

Where conditions permit snow caves are another way to shelter high on the mountain. Some climbers do not use tents at high altitudes unless the snow conditions do not allow for snow caving, since snow caves are silent and much warmer than tents. They can be built relatively easily, given sufficient time, using a snow shovel. A correctly made snow cave will hover around freezing, which relative to outside temperatures can be very warm. They can be dug anywhere where there is at least four feet of snow. The addition of a good quality bivvy bag and closed cell foam sleeping mat will also increase the warmth of the snow cave. Another shelter that works well is a quinzee, which is excavated from a pile of snow that has been work hardened or sintered (typically by stomping). Igloos are used by some climbers, but are deceptively difficult to build and require specific snow conditions.

Hazards

Mountaineering is considered to be one of the most dangerous activities in the world. Loss of life is not uncommon on most major extreme altitude mountaineering destinations every year. Dangers in mountaineering are sometimes divided into two categories: objective hazards that exist without regard to the climber's presence, like rockfall, avalanches and inclement weather, and subjective hazards that relate only to factors introduced by the climber. Equipment failure and falls due to inattention, fatigue or inadequate technique are examples of subjective hazards. A route continually swept by avalanches and storms is said to have a high level of objective danger, whereas a technically far more difficult route that is relatively safe from these dangers may be regarded as objectively safer.

In all, mountaineers must concern themselves with dangers: falling rocks, falling ice, snow-avalanches, the climber falling, falls from ice slopes, falls down snow slopes, falls into crevasses and the dangers from altitude and weather.[4] To select and follow a route using one's skills and experience to mitigate these dangers is to exercise the climber's craft.

Falling rocks

Every rock mountain is slowly disintegrating due to erosion, the process being especially rapid above the snow-line. Rock faces are constantly swept by falling stones, which may be possible to dodge. Falling rocks tend to form furrows in a mountain face, and these furrows (couloirs) have to be ascended with caution, their sides often being safe when the middle is stoneswept. Rocks fall more frequently on some days than on others, according to the recent weather. Ice formed during the night may temporarily bind rocks to the face but warmth of the day or lubricating water from melting snow or rain may easily dislodge these rocks. Local experience is a valuable help on determining typical rock fall on such routes.

The direction of the dip of rock strata sometimes determines the degree of danger on a particular face; the character of the rock must also be considered. Where stones fall frequently debris will be found below, whilst on snow slopes falling stones cut furrows visible from a great distance. In planning an ascent of a new peak or an unfamiliar route, mountaineers must look for such traces. When falling stones get mixed in considerable quantity with slushy snow or water a mud avalanche is formed (common in the Himalayas). It is vital to avoid camping in their possible line of fall.

Falling ice

The places where ice may fall can always be determined beforehand. It falls in the broken parts of glaciers (seracs) and from overhanging cornices formed on the crests of narrow ridges. Large icicles are often formed on steep rock faces, and these fall frequently in fine weather following cold and stormy days. They have to be avoided like falling stones. Seracs are slow in formation, and slow in arriving (by glacier motion) at a condition of unstable equilibrium. They generally fall in or just after the hottest part of the day. A skillful and experienced ice-man will usually devise a safe route through a most intricate ice-fall, but such places should be avoided in the afternoon of a hot day. Hanging glaciers (i.e. glaciers perched on steep slopes) often discharge themselves over steep rock-faces, the snout breaking off at intervals. They can always be detected by their debris below. Their track should be avoided.

Falls from rocks

A rock climber's skill is shown by their choice of handhold and foothold, and their adhesion to the holds once chosen. Much depends on the ability to estimate the capability of the rock to support the weight placed on it. Many loose rocks are quite firm enough to bear a person's weight, but experience is needed to know which can be trusted, and skill is required in transferring the weight to them without jerking. On rotten rocks the rope must be handled with special care, lest it should dislodge loose stones on to those below. Similar care must be given to handholds and footholds, for the same reason. When a horizontal traverse has to be made across very difficult rocks, a dangerous situation may arise unless at both ends of the traverse there are firm positions. Mutual assistance on hard rocks takes all manner of forms: two, or even three, people climbing on one another's shoulders, or using an ice axe propped up by others for a foothold. The great principle is that of co-operation, all the members of the party climbing with reference to the others, and not as independent units; each when moving must know what the climber in front and the one behind are doing. After bad weather steep rocks are often found covered with a veneer of ice (verglas), which may even render them inaccessible. Crampons are useful on such occasions.

Avalanches

Every year, 120 to 150 people die in small avalanches in the Alps alone. The vast majority are reasonably experienced male skiers aged 20–35 but also include ski instructors and guides. There is always a lot of pressure to risk a snow crossing. Turning back takes a lot of extra time and effort, supreme leadership, and most importantly there is seldom an avalanche that proves the right decision was made. Making the decision to turn around is especially hard if others are crossing the slope, but any next person could become the trigger.

There are many types of avalanche, but two types are of the most concern. These are Snow Avalanches and Ice Avalanches:

Snow Avalanches

  1. Slab avalanche
    This type of avalanche occurs when a plate of snow breaks loose and starts sliding downhill; these are the largest and most dangerous.
    1. Hard slab avalanche
    This type of avalanche is formed by hard-packed snow in a cohesive slab. The slab will not break up easily as it slides down the hill, resulting in large blocks tumbling down the mountain.
    1. Soft slab avalanche
    This type of avalanche is formed again by a cohesive layer of snow bonded together, the slab tends to break up more easily.
  2. Loose snow avalanche
    This type of avalanche is triggered by a small amount of moving snow that accumulates into a big slide. Also known as a "wet slide or point release" avalanche. This type of avalanche is deceptively dangerous as it can still knock a climber or skier off their feet and bury them, or sweep them over a cliff into a terrain trap.

Dangerous slides are most likely to occur on the same slopes preferred by many skiers: long and wide open, few trees or large rocks, 30 to 45 degrees of angle, large load of fresh snow, soon after a big storm, on a slope "lee to the storm". Solar radiation can trigger slides as well. These will typically be a point release or wet slough type of avalanche. The added weight of the wet slide can trigger a slab avalanche. Ninety percent of reported victims are caught in avalanches triggered by themselves or others in their group.

Ice Avalanches are a hazard that exists in glaciated mountain ranges. They are caused by the collapse of unstable ice blocks from a steep or overhanging part of a glacier, referred to as a hanging glacier. Due to the fact that they are part of a glacier, ice avalanches can have large amounts of rock in them. Ice avalanches are quite dangerous because they can travel long distances, sometimes as far as 8km out onto the glacier valley floor. Ice avalanches are a common everyday occurrence in ranges such as the Alaska Range, Saint Elias Mountains, or Columbia Icefield.

When going off-piste or travelling in alpine terrain, parties are advised to always carry:

  1. avalanche beacon
  2. probe
  3. shovel (retrieving victims with a shovel instead of hands is five times faster)

They are also advised to have had avalanche training. Ironically, expert skiers who have avalanche training make up a large percentage of avalanche fatalities; perhaps because they are the ones more likely to ski in areas prone to avalanches, and certainly because most people do not practice enough with their equipment to be truly fast and efficient rescuers.

Even with proper rescue equipment and training, there is a one-in-five chance of dying if caught in a significant avalanche, and only a 50/50 chance of being found alive if buried more than a few minutes. The best solution is to learn how to avoid risky conditions.

Ice slopes

For travel on slopes consisting of ice or hard snow, crampons are a standard part of a mountaineer's equipment. While step-cutting can sometimes be used on snow slopes of moderate angle, this can be a slow and tiring process, which does not provide the higher security of crampons. However, in soft snow or powder, crampons are easily hampered by balling of snow, which reduces their effectiveness. In either case, an ice axe not only assists with balance but provides the climber with the possibility of self-arrest in case of a slip or fall. On a true ice slope however, an ice axe is rarely able to effect a self-arrest. As an additional safety precaution on steep ice slopes, the climbing rope is attached to ice screws buried into the ice.

Snow slopes

Snow slopes are very common, and usually easy to ascend. At the foot of a snow or ice slope is generally a big crevasse, called a bergschrund, where the final slope of the mountain rises from a snow-field or glacier. Such bergschrunds are generally too wide to be stepped across, and must be crossed by a snow bridge, which needs careful testing and a painstaking use of the rope. A steep snow slope in bad condition may be dangerous, as the whole body of snow may start as an avalanche. Such slopes are less dangerous if ascended directly, rather than obliquely, for an oblique or horizontal track cuts them across and facilitates movement of the mass. New snow lying on ice is especially dangerous. Experience is needed for determining the feasibility of advancement over snow in doubtful condition. Snow on rocks is usually rotten unless it is thick; snow on snow is likely to be sound. A day or two of fine weather will usually bring new snow into sound condition. Snow cannot lie at a very steep angle, though it often deceives the eye as to its slope. Snow slopes seldom exceed 40°. Ice slopes may be much steeper. Snow slopes in early morning are usually hard and safe, but the same in the afternoon are quite soft and possibly dangerous; hence the advantage of an early start.

Crevasses

Crevasses are the slits or deep chasms formed in the substance of a glacier as it passes over an uneven bed. They may be open or hidden. In the lower part of a glacier the crevasses are open. Above the snow-line they are frequently hidden by arched-over accumulations of winter snow. The detection of hidden crevasses requires care and experience. After a fresh fall of snow they can only be detected by sounding with the pole of the ice axe, or by looking to right and left where the open extension of a partially hidden crevasse may be obvious. The safeguard against accident is the rope, and no one should ever cross a snow-covered glacier unless roped to one, or even better to two companions. Anyone venturing onto crevasses should be trained in crevasse rescue.

Weather

The primary dangers caused by bad weather centre around the changes it causes in snow and rock conditions, making movement suddenly much more arduous and hazardous than under normal circumstances. Whiteouts make it difficult to retrace a route while rain may prevent taking the easiest line only determined as such under dry conditions. In a storm the mountaineer who uses a compass for guidance has a great advantage over a merely empirical observer. In large snow-fields it is, of course, easier to go wrong than on rocks, but intelligence and experience are the best guides in safely navigating objective hazards.

Summer thunderstorms may produce intense lightning.[4] If a climber happens to be standing on or near the summit, they risk being struck. There are many cases where people have been struck by lightning while climbing mountains. In most mountainous regions, local storms develop by late morning and early afternoon. Many climbers will get an "alpine start"; that is before or by first light so as to be on the way down when storms are intensifying in activity and lightning and other weather hazards are a distinct threat to safety. High winds can speed the onset of hypothermia, as well as damage equipment such as tents used for shelter.[4][5] Under certain conditions, storms can also create waterfalls which can slow or stop climbing progress. A notable example is the Fohn wind acting upon the Eiger.

Altitude

Rapid ascent can lead to altitude sickness.[4][6] The best treatment is to descend immediately. The climber's motto at high altitude is "climb high, sleep low", referring to the regimen of climbing higher to acclimatise but returning to lower elevation to sleep. In the South American Andes, the chewing of coca leaves has been traditionally used to treat altitude sickness symptoms.

Common symptoms of altitude sickness include severe headache, sleep problems, nausea, lack of appetite, lethargy and body ache. Mountain sickness may progress to HACE (High Altitude Cerebral Edema) and HAPE (High Altitude Pulmonary Edema), both of which can be fatal within 24 hours.[4][6][7]

In high mountains, atmospheric pressure is lower and this means that less oxygen is available to breathe.[4] This is the underlying cause of altitude sickness. Everyone needs to acclimatise, even exceptional mountaineers that have been to high altitude before.[8] Generally speaking, mountaineers start using bottled oxygen when they climb above 7,000 m. Exceptional mountaineers have climbed 8000-metre peaks (including Everest) without oxygen, almost always with a carefully planned program of acclimatisation.

Solar radiation

Solar radiation increases significantly as the atmosphere gets thinner with increasing altitude thereby absorbing less ultraviolet radiation.[4][5] Snow cover reflecting the radiation can amplify the effects by up to 75% increasing the risks and damage from sunburn and snow blindness.[5]

In 2005, researcher and mountaineer John Semple established that above-average ozone concentrations on the Tibetan plateau may pose an additional risk to climbers.[9]

Volcanic activity

Some mountains are active volcanoes as in the case of the many stratovolcanoes that form the highest peaks in island arcs and in parts of the Andes. Some of these volcanic mountains may cause several hazards if they erupt, such as lahars, pyroclastic flows, rockfalls, lava flows, heavy tephra fall, volcanic bomb ejections and toxic gases.

Styles of mountaineering

There are two main styles of mountaineering: Expedition Climbing and Alpine Climbing.

In Europe alpine climbing is often referred to as Alpinism. A mountaineer who adopts this style of climbing is referred to as an Alpine Mountaineer. In Europe an alpine mountaineer is sometimes referred to as an Alpinist. Alpine Mountaineers are typically found climbing in medium-sized glaciated mountain areas such as the Alps or Rocky Mountains. Medium-sized generally refers to altitudes in the intermediate altitude (7,000' to 12,000') and first half of high altitude (12,000' to 18,000') ranges. However, alpine style ascents have been done throughout history on extreme altitude (18,000' to 29,000') peaks also, albeit in lower volume to expedition style ascents. Alpine climbing refers to a particular style of mountain climbing that involves a mixture of snow climbing, ice climbing, rock climbing, and glacier travel, where climbers generally single carry their loads between camps, in a single push for the summit. Light and fast is the mantra of the Alpine Mountaineer. The term alpinism contrasts with expedition style climbing (as commonly undertaken in the Himalayan region or other large ranges of the world), which could be viewed as slow and heavy, where climbers may use porters, pack animals, glacier airplanes, cooks, multiple carries between camps, usage of fixed lines etc. A mountaineer who adopts this style of climbing is referred to as an Expedition Mountaineer. Expedition mountaineers still employ the skill sets of the alpine mountaineer, except they have to deal with even higher altitudes, expanded time scale, longer routes, foreign logistics, more severe weather, and additional skills unique to expeditionary climbing. The prevalence of expedition style climbing in the Himalaya is largely a function of the nature of the mountains in the region. Because Himalayan base camps can take days or weeks to trek to, and Himalayan mountains can take weeks or perhaps even months to climb, a large number of personnel and amount of supplies are necessary. This is why expedition style climbing is frequently used on large and isolated peaks in the Himalaya. In Europe and North America there is less of a need for expedition style climbing on most medium-sized mountains. These mountains can often be easily accessed by car or air, are at a lower altitude and can be climbed in a shorter time scale. Expedition style mountaineering can be found in the larger high altitude and extreme altitude North American ranges such as the Alaska Range and Saint Elias Mountains. These remote mountaineering destinations can require up to a 2 week trek by foot, just to make it to base camp. Most expeditions in these regions choose a glacier flight to basecamp. Route length in days from basecamp can vary in these regions, typically from 10 days to 1 month during the climbing season. Winter mountaineering on major peaks in these ranges can generally consume between 30 to 60 days depending on the route, and can generally only be tackled via expedition style mountaineering during this season.

The differences between, and advantages and disadvantages of, the two kinds of climbing are as follows:[2]

Expedition Climbing

Alpine Climbing

Locations

Mountaineering has become a popular sport throughout the world. In Europe the sport largely originated in the Alps, and is still immensely popular there. Other notable mountain ranges frequented by climbers include the Caucasus, the Pyrenees, Rila mountains, the Tatra mountains and Carpathian Mountains. In North America climbers frequent the Rocky Mountains, the Sierra Nevada of California, the Cascades of the Pacific Northwest, the high peaks of The Alaska Range and Saint Elias Mountains. There has been a long tradition of climbers going on expeditions to the Greater Ranges, a term generally used for the Andes and the high peaks of Asia including the Himalaya, Karakoram, Pamirs and Tien Shan. In the past this was often on exploratory trips or to make first ascents. With the advent of cheaper, long-haul air travel, mountaineering holidays in the Greater Ranges are now undertaken much more frequently and ascents of even Everest and Vinson Massif (the highest mountain in Antarctica) are offered as a "package holiday". Other mountaineering areas of interest include the Southern Alps of New Zealand, the Japanese Alps, the South Korean mountains, the Coast Mountains of British Columbia, the Scottish Highlands, and the mountains of Scandinavia, especially Norway.

History

Further reading

See also

References

  1. ^ "Nepal Mountaineering Association". web page. 2008. http://www.nepalmountaineering.org/index.php?razer=peak_detail&&name=Imja-tse(Island%20Peak). Retrieved 2 June 2011. 
  2. ^ a b Cox, Steven M. and Kris Fulsaas, ed., ed (2003-09). Mountaineering: The Freedom of the Hills (7 ed.). Seattle: The Mountaineers. ISBN 0898868289. 
  3. ^ UIAA Activities. UIAA. http://theuiaa.org/activities.html 
  4. ^ a b c d e f g Cymerman, A; Rock, PB. Medical Problems in High Mountain Environments. A Handbook for Medical Officers. USARIEM-TN94-2. US Army Research Inst. of Environmental Medicine Thermal and Mountain Medicine Division Technical Report. http://archive.rubicon-foundation.org/7976. Retrieved 2009-03-05. 
  5. ^ a b c Hamilton, AJ. Biomedical Aspects of Military Operations at High Altitude. USARIEM-M-30/88. US Army Research Inst. of Environmental Medicine Thermal and Mountain Medicine Division Technical Report. http://archive.rubicon-foundation.org/7975. Retrieved 2009-03-05. 
  6. ^ a b Roach, Robert; Stepanek, Jan; and Hackett, Peter. (2002). "24". Acute Mountain Sickness and High-Altitude Cerebral Edema. In: Medical Aspects of Harsh Environments. 2. Washington, DC. http://www.bordeninstitute.army.mil/published_volumes/harshEnv2/harshEnv2.html. Retrieved 2009-01-05. 
  7. ^ Roach, James M. and Schoene, Robert B. (2002). "25". High-Altitude Pulmonary Edema. In: Medical Aspects of Harsh Environments. 2. Washington, DC. http://www.bordeninstitute.army.mil/published_volumes/harshEnv2/harshEnv2.html. Retrieved 2009-01-05. 
  8. ^ Muza, SR; Fulco, CS; Cymerman, A (2004). "Altitude Acclimatization Guide.". US Army Research Inst. of Environmental Medicine Thermal and Mountain Medicine Division Technical Report (USARIEM–TN–04–05). http://archive.rubicon-foundation.org/7616. Retrieved 2009-03-05. 
  9. ^ Mountainous plateau creates ozone "halo" around Tibet
  10. ^ Lynn Thorndike, Renaissance or Prenaissance, Journal of the History of Ideas, Vol. 4, No. 1. (Jan., 1943), pp. 69-74.
  11. ^ The Ascent of Mount Ventoux http://www.idehist.uu.se/distans/ilmh/Ren/ren-pet-ventoux.htm http://www.fordham.edu/halsall/source/petrarch-ventoux.html http://petrarch.petersadlon.com/read_letters.html?s=pet17.html
  12. ^ Cameron, Ian (1990). Kingdom of the Sun God: a history of the Andes and their people. New York: Facts on File. pp. 174–175. ISBN 0-8160-2581-9. 
  13. ^ Mackinder, Halford John (May 1900). "A Journey to the Summit of Mount Kenya, British East Africa". The Geographical Journal 15 (5): 453–476. doi:10.2307/1774261. JSTOR 1774261. 
  14. ^ Cohen, Michael P., The History of the Sierra Club 1892-1970 (Sierra Club Books, San Francisco, 1988) ISBN 0-87156-732-6
  15. ^ Which Events are Olympic? Olympics at Sports Reference.com, 2008

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