Rafter

Rafting
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For other uses, see Rafting (disambiguation).

Rafting in Brazil.

River rafting in Ladakh, India.

Rafting on the Arkansas River.
Rafting or whitewater rafting is a challenging recreational activity utilizing a raft to navigate a river or other bodies of water. This is usually done on whitewater or different degrees of rough water, in order to thrill and excite the raft passengers. The development of this activity as a leisure sport has become popular since the mid 1970s.
Contents[hide]
1 History
2 Whitewater rafts
3 Classes of Whitewater
4 Safety
5 Issues with rafting
6 See also
7 References
8 External links
//

[edit] History
Rafting is one of the earliest means of transportation, used as a means for shipping people, hunting, and transferring food.
In 1842, Lieutenant John Fremont of the U.S. Army first journalized his rafting expedition on the Platte River. Horace H. Day designed the equipment he used in rafting. Day’s rafts were constructed from four independent rubber cloth tubes and wrap-around floor. [1]
In 1960s, rafting was then recognized and paths like Grand Canyon were routed and whitewater rafting companies were established.
In 1970s, rafting marked its major development as a leisure sport when it was then included in the Munich Olympic Games.
In 1980s, as rafting continued to gain its popularity, many rivers were opened for rafting activities including rivers in South America and Africa.
In 1990s, rafting was included in major game events like the Barcelona Games in 1992, Atlanta Games in 1996, and the whitewater events of the Summer Olympic Games hosted by Ocoee River in Tennessee Valley. In addition, the International Federation of Rafting was instituted in 1997 and in 1999 the first Official International Championship was held.
Currently, river rafting is still gaining popularity among extreme water sports in order to thrill and excite the raft passengers.[citation needed]

[edit] Whitewater rafts
Rafts were originally the simplest form of man’s transportation in water and were then made of several logs, planks or reeds which were fastened together. Nowadays, inflatable boat were used as rafts which were later adopted by the military for beach assaults. It consists of very durable, multi-layered rubberized or vinyl fabrics with several independent air chambers. Its length varies between 3.5 m (11 ft) and 6 m (20 ft), the width between 1.8 m (6 ft) and 2.5 m (8 ft). The exception to this size rule is usually the packraft, which is designed as a portable single-person raft and may be as small as 1.5m long and weigh as little as 4 lbs.
Rafts come in a few different forms. In Europe the most common is the symmetrical raft steered with a paddle at the stern. Other types are the asymmetrical, rudder-controlled raft and the symmetrical raft with central helm (oars). Rafts are usually propelled with ordinary paddles and typically hold 4 to 12 persons. In Russia rafts are often hand made and are often a catamaran style with two inflatable tubes attached to a frame. Pairs of paddlers navigate these rafts. Catamaran style rafts have become popular in the western United States as well, but are typically rowed instead of paddled.
Rivers with high current are used for White water rafting. Specially, White Water Rafting is popular in Nepal due to high current of water falling through hills and rocky mountains.

[edit] Classes of Whitewater
Main article: International Scale of River Difficulty
Class 1: Very small rough areas, requires no maneuvering. (Skill Level: None)Class 2: Some rough water, maybe some rocks, might require maneuvering.(Skill Level: Basic Paddling Skill)Class 3: Whitewater, small waves, maybe a small drop, but no considerable danger. May require significant maneuvering.(Skill Level: Experienced paddling skills)Class 4: Whitewater, medium waves, maybe rocks, maybe a considerable drop, sharp maneuvers may be needed. (Skill Level: Whitewater Experience)Class 5: Whitewater, large waves, possibility of large rocks and hazards, possibility of a large drop, requires precise maneuvering (Skill Level: Advanced Whitewater Experience)Class 6: Class 6 rapids are considered to be so dangerous as to be effectively unnavigable on a reliably safe basis. Rafters can expect to encounter substantial whitewater, huge waves, huge rocks and hazards, and/or substantial drops that will impart severe impacts beyond the structural capacities and impact ratings of most all rafting equipment. Traversing a Class 6 rapid has a dramatically increased likelihood of ending in serious injury or death compared to lesser classes. (Skill Level: Successful completion of a Class 6 rapid without serious injury or death is widely considered to be a matter of luck or extreme skill)

[edit] Safety

Packrafting in Alaska.
Whitewater rafting can be a dangerous sport, especially if basic safety precautions are not observed. Both commercial and private trips have seen their share of injuries and fatalities, though private travel has typically been associated with greater risk. Depending on the area, legislated safety measures may exist for rafting operators. These range from certification of outfitters, rafts, and raft leaders, to more stringent regulations about equipment and procedures. It is generally advisable to discuss safety measures with a rafting operator before signing on for a trip. The equipment used and the qualifications of the company and raft guides are essential information to be considered.
Like most outdoor sports, rafting in general has become safer over the years. Expertise in the sport has increased, and equipment has become more specialized and increased in quality. As a result the difficulty rating of most river runs has changed. A classic example would be the Colorado River in the Grand Canyon, which has swallowed whole expeditions in the past, leaving only fragments of boats but is now run safely by commercial outfitters hundreds of times each year, with relatively untrained passengers. [2]
Risks in whitewater rafting stem from both environmental dangers and from improper behavior. Certain features on rivers are inherently unsafe and have remained consistently so despite the passage of time. These would include "keeper hydraulics", "strainers" (e.g. fallen trees), dams (especially low-head dams, which tend to produce river-wide keeper hydraulics), undercut rocks, and of course dangerously high waterfalls. Rafting with experienced guides is the safest way to avoid such features. Even in safe areas, however, moving water can always present risks -- such as when a swimmer attempts to stand up on a rocky riverbed in strong current, risking foot entrapment. Irresponsible behavior related to rafting while intoxicated has also contributed to many accidents.
To combat the illusion that rafting is akin to an amusement park ride, and to underscore the personal responsibility each rafter faces on a trip, rafting outfitters generally require customers to sign waiver forms indicating understanding and acceptance of potential serious risks. Rafting trips often begin with safety presentations to educate customers about problems that may arise.
Due to this the overall risk level on a rafting trip with experienced guides using proper precautions is low.[citation needed] Thousands of people safely enjoy raft trips every year.

[edit] Issues with rafting

Rafting in Montenegro.
Like all wilderness sports, rafting has to balance the conflict between nature protection and nature use. Because of frequent problems in the past, some rivers now have regulations restricting or specifying the annual and daily operating times.
Conflicts have also arisen with environmentalists when rafting operators, often in co-operation with municipalities and tourism associations, alter the riverbed by dredging and/or blasting in order to eliminate safety risks or create more interesting whitewater features in the river. Incongruously these measures usually are only temporary, since a riverbed is subject to permanent changes.
On the other hand, rafting contributes to the economy of many alpine regions which in turn may contribute to the protection of rivers from hydroelectric power generation and other development. Additionally, white water rafting trips can promote environmentalism. By experiencing first hand the beauty of a given river, individuals who would otherwise be indifferent to the environmental concerns of an area may gain a strong desire to protect and preserve that area because of a positive outdoors experience.

adventure mountain

Mountain
From Wikipedia, the free encyclopedia
Jump to: navigation, search
For other uses, see Mountain (disambiguation).

Mount Damavand, Iran

Blue Ridge Mountains in Shenandoah National Park, Virginia, USA
A mountain is a landform that extends above the surrounding terrain in a limited area, with a peak. A mountain is generally steeper than a hill, but there is no universally accepted standard definition for the height of a mountain or a hill although a mountain usually has an identifiable summit. Mountains cover 64% of Asia, 36% of North America, 25% of Europe, 22% of South America, 17% of Australia, and 3% of Africa. As a whole, 24% of the Earth's land mass is mountainous. 10% of people live in mountainous regions. Most of the world's rivers are fed from mountain sources, and more than half of humanity depends on mountains for water.[1][2]
The adjective montane is used to describe mountainous areas and things associated with them.
Contents[hide]
1 Definitions
1.1 In the United Kingdom
1.2 In the United States
1.3 Height
2 Characteristics
3 Types of mountains
4 Geology
5 See also
6 Gallery
7 References
//

[edit] Definitions

Ben Nevis, a 1344 m (4409 ft) munro, Grampian Mountains, Scotland
Some authorities define a mountain as a peak with a topographic prominence over a defined value: for example, according to the Britannica Student Encyclopedia, the term "generally refers to rises over 2,000 feet (610 m)".[3] The Encyclopædia Britannica, on the other hand, does not prescribe any height, merely stating that "the term has no standardized geological meaning".[4]

[edit] In the United Kingdom
In England and Wales the Department for Environment, Food and Rural Affairs has defined "mountain" (as a mass noun) as all land over 600 metres for the purposes of right to roam legislation.[5] The Land Reform (Scotland) Act 2003 does not appear to draw this distinction, and in Scotland the term "mountain" is more subjective, often being used for hills exceeding 3,000 feet (914.4 m) listed as Munros. In the United Kingdom the term "hill" is commonly used for all hills and mountains, regardless of height.

Fowler Mountain of Connecticut, only 750 feet (229 m), is considered a mountain locally.

[edit] In the United States
In the United States, the U.S. Board on Geographic Names lists hundreds of landscape features under 1,000 feet (305 m) (some as low as 100 feet) named as "mountains." This is true for all parts of the United States, including the west coast where such lofty ranges as the Cascade Mountains dominate. And yet the Board does not attempt to distinguish between such features as mountains, hills, or other prominences, and simply categorizes all of them as summit, regardless of what they are called or how high they are. However, the Board does list and categorize such low mountain ranges as the Mount Tom Range (with a high point of 1,200 feet; 366 m) as range.[1]

[edit] Height

K2, 8,611 metres (28,250 ft), Karakoram Range, Pakistan.
The height of a mountain is measured as the elevation of its summit above mean sea level. The Himalayas average 5 km above sea level, while the Andes average 4 km. The highest mountain on land is Everest, 8,848 metres (29,030 ft) in the Himalayas.
Other definitions of height are possible. The peak that is farthest from the center of the Earth is Chimborazo in Ecuador. At 6,267 metres (20,560 ft) above sea level it is not even the tallest peak in the Andes, but because Chimborazo is very close to the equator and the Earth bulges at the equator, it is 2,150 metres (7,100 ft) further away from the Earth's center than Everest.[6] The peak that rises farthest from its base is Mauna Kea on Hawaii, whose peak is 10,200 metres (33,500 ft) above its base on the floor of the Pacific Ocean.[7] Mount Lamlam on Guam also lays claim to the tallest mountain as measured from it base. Although its peak is only 406 metres (1,330 ft) above sea level, it measures 11,530 metres (37,830 ft) to its base at the bottom of the Marianas Trench.[8]
Even though Everest is the highest mountain on Earth today, there have been much taller mountains in the past. During the Precambrian era, the Canadian Shield once had mountains 12,000 m (39,370 ft)[9] in height that are now eroded down into rolling hills. These formed by the collision of tectonic plates much like the Himalaya and the Rocky Mountains.
At 26 kilometres (85,000 ft) (Fraknoi et al., 2004), the tallest known mountain in the solar system is Olympus Mons, located on Mars and is an ancient volcano. Volcanoes have been known to erupt on other planets and moons in our solar system in our life-times (volcanoes on Venus for example, constantly erupt) and some of them erupt ice instead of lava. Several years ago, the Hale telescope recorded the first known live images of a volcano erupting on a moon in our solar system.

[edit] Characteristics
High mountains, and mountains located closer to the Earth's poles, have elevations that exist in colder layers of the atmosphere. They are consequently often subject to glaciation and erosion through frost action. Such processes produce the popularly recognizable mountain peak shape. Some of these mountains have glacial lakes, created by melting glaciers; for example, there are an estimated 3,000 glacial lakes in Bhutan.

Mount Olympus in Greece.
Sufficiently tall mountains have very different climatic conditions at the top than at the base, and will thus have different life zones at different altitudes. The flora and fauna found in these zones tend to become isolated since the conditions above and below a particular zone will be inhospitable to those organisms. These isolated ecological systems are known as sky islands and/or microclimates. Tree forests are forests on mountain sides which attract moisture from the trees, creating a unique ecosystem. Very tall mountains may be covered in ice or snow.
Mountains are colder than lower ground, because the Sun heats Earth from the ground up. The Sun's radiation travels through the atmosphere to the ground, where Earth absorbs the heat. Air closest to the Earth's surface is, in general, warmest (see lapse rate for details). Air as high as a mountain is poorly warmed and, therefore, cold.[10] Air temperature normally drops 1 to 2 degrees Celsius (1.8 to 3.6 degrees Fahrenheit) for each 300 meters (1000 feet) of altitude.
Mountains are generally less preferable for human habitation than lowlands; the weather is often harsher, and there is little level ground suitable for agriculture. At very high altitudes, there is less oxygen in the air and less protection against solar radiation (UV). Acute mountain sickness (caused by hypoxia - a lack of oxygen in the blood) affects over half of lowlanders who spend more than a few hours above 3,500 meters (11,483 feet).
A number of mountains and mountain ranges of the world have been left in their natural state, and are today primarily used for recreation, while others are used for logging, mining, grazing, or see little use of any sort at all. Some mountains offer spectacular views from their summits, while others are densely wooded. Summit accessibility ranges from mountain to mountain; height, steepness, latitude, terrain, weather, and the presence or lack thereof of roads, lifts, or tramways are all factors that affect accessibility. Hiking, backpacking, mountaineering, rock climbing, ice climbing, downhill skiing, and snowboarding are recreational activities typically enjoyed on mountains. Mountains that support heavy recreational use (especially downhill skiing) are often the locations of mountain resorts.

[edit] Types of mountains

The Matterhorn, the classical pyramidal peak
Mountains can be characterized in several ways. Some mountains are volcanoes and can be characterized by the type of lava and eruptive history. Other mountains are shaped by glacial processes and can be characterized by their glaciated features. Still others are typified by the faulting and folding of the Earth's crust, or by the collision of continental plates via plate tectonics (the Himalayas, for instance). Shape and placement within the overall landscape also define mountains and mountainous structures (such as butte and monadnock). Finally, many mountains can be characterized by the type of rock that make up their composition. More information on mountain types can be found in List of mountain types.

[edit] Geology
The Himalayan mountain range with Mount Everest.
A mountain is usually produced by the movement of lithospheric plates, either orogenic movement or epeirogenic movement. The compressional forces, isostatic uplift and intrusion of igneous matter forces surface rock upwards, creating a landform higher than the surrounding features. The height of the feature makes it either a hill or, if higher and steeper, a mountain. The absolute heights of features termed mountains and hills vary greatly according to an area's terrain. The major mountains tend to occur in long linear arcs, indicating tectonic plate boundaries and activity. Two types of mountain are formed depending on how the rock reacts to the tectonic forces – block mountains or fold mountains.
The compressional forces in continental collisions may cause the compressed region to thicken, so the upper surface is forced upwards. In order to balance the weight of the earth suface, much of the compressed rock is forced downwards, producing deep "mountain roots"[see the Book of "Earth", Press and Siever page.413]. These roots are deeply embedded in the ground, thus, a mountain have a shape like peg [See Anatomy of the Earth, Cailleus page.220]. Mountains therefore form downwards as well as upwards (see isostasy). However, in some continental collisions part of one continent may simply override part of the others, crumpling in the process.
Some isolated mountains were produced by volcanoes, including many apparently small islands that reach a great height above the ocean floor.
Block mountains are created when large areas are widely broken up by faults creating large vertical displacements. This occurrence is fairly common. The uplifted blocks are block mountains or horsts. The intervening dropped blocks are termed graben: these can be small or form extensive rift valley systems. This form of landscape can be seen in East Africa, the Vosges, the Basin and Range province of Western North America and the Rhine valley. These areas often occur when the regional stress is extensional and the crust is thinned.
The mid-ocean ridges are often referred to as undersea mountain ranges due to their bathymetric prominence.
Where rock does not fault it folds, either symmetrically or asymmetrically. The upfolds are anticlines and the downfolds are synclines; in asymmetric folding there may also be recumbent and overturned folds. The Jura mountains are an example of folding. Over time, erosion can bring about an inversion of relief: the soft upthrust rock is worn away so the anticlines are actually lower than the tougher, more compressed rock of the synclines.

[edit] See also
List of mountains
List of highest mountains
Category:Lists of mountains
Latin names of mountains
Mountain range and list of mountain ranges
Mountaineering
List of ski areas and resorts
List of peaks by prominence

[edit] Gallery

Mount Everest, 8,848 metres (29,030 ft), Himalayas, Nepal.

Mount Kilimanjaro, 5,895 metres (19,340 ft), Tanzania.

Mount Feathertop, 1,922 metres (6,310 ft), Great Dividing Range, Victoria, Australia

Pilot Mountain, 738 metres (2,420 ft), Sauratown Mountains, North Carolina, United States

Northern Appalachian Mountains, Chic-Choc Range, Gaspé Peninsula, Quebec, Canada

Yu Shan (Jade Mountain), 3,952 metres (12,970 ft), Taiwan.

Finsteraarhorn, 4,274 metres (14,020 ft), Bernese Alps, Switzerland.

Sugarloaf Mountain, Brazil, 396 metres (1,300 ft), Rio de Janeiro, Brazil.

Table Mountain Cape Town, South Africa

[edit] References

Wikiquote has a collection of quotations related to:
Mountains

Wikimedia Commons has media related to:
Gallery of mountains
^ "International Year of Freshwater 2003". Retrieved on 2006-12-07.
^ "The Mountain Institute". Retrieved on 2006-12-07.
^ "Mountain -- Britannica Student Encyclopedia". Retrieved on 2007-01-08.
^ "Mountain -- Britannica Concise Encyclopedia - The online encyclopedia you can trust!". Retrieved on 2007-01-08.
^ UK Department for Environment, Food and Rural Affairs
^ The 'Highest' Spot on Earth? : NPR
^ Eruptions of Hawaiian Volcanoes [USGS]
^ Geography of Guam
^ Clark, Bruce W. (1999). "Geologic History", Making Connections: Canada's Geography. Scarborough, Ontario: Prentice Hall Ginn Canada, pp. 95. ISBN 0-13-012635-7.
^ Why is it colder in the mountains than in the valley?