1.
North America
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North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be considered a subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. North America covers an area of about 24,709,000 square kilometers, about 16. 5% of the land area. North America is the third largest continent by area, following Asia and Africa, and the fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7. 5% of the worlds population, North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge. The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago, the Classic stage spans roughly the 6th to 13th centuries. The Pre-Columbian era ended with the migrations and the arrival of European settlers during the Age of Discovery. Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists, indigenous peoples, African slaves and their descendants, European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south. Because of the history of colonialism, most North Americans speak English, Spanish or French, the Americas are usually accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass previously unknown by Europeans. In 1507, Waldseemüller produced a map, in which he placed the word America on the continent of South America. He explained the rationale for the name in the accompanying book Cosmographiae Introductio, for Waldseemüller, no one should object to the naming of the land after its discoverer. He used the Latinized version of Vespuccis name, but in its feminine form America, following the examples of Europa, Asia and Africa. Later, other mapmakers extended the name America to the continent, In 1538. Some argue that the convention is to use the surname for naming discoveries except in the case of royalty, a minutely explored belief that has been advanced is that America was named for a Spanish sailor bearing the ancient Visigothic name of Amairick. Another is that the name is rooted in a Native American language, the term North America maintains various definitions in accordance with location and context. In Canadian English, North America may be used to refer to the United States, alternatively, usage sometimes includes Greenland and Mexico, as well as offshore islands
2.
Rocky Mountains
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The Rocky Mountains, commonly known as the Rockies, are a major mountain range in western North America. The Rocky Mountains stretch more than 3,000 miles from the northernmost part of British Columbia, in western Canada, to New Mexico, in the Southwestern United States. Within the North American Cordillera, the Rockies are somewhat distinct from the Pacific Coast Ranges, the Rocky Mountains were initially formed from 80 million to 55 million years ago during the Laramide orogeny, in which a number of plates began to slide underneath the North American plate. The angle of subduction was shallow, resulting in a belt of mountains running down western North America. Since then, further tectonic activity and erosion by glaciers have sculpted the Rockies into dramatic peaks, at the end of the last ice age, humans started to inhabit the mountain range. The first mention of their present name by a European was in the journal of Jacques Legardeur de Saint-Pierre in 1752, the Rocky Mountains are commonly defined as stretching from the Liard River in British Columbia south to the Rio Grande in New Mexico. The United States definition of the Rockies includes the Cabinet and Salish Mountains of Idaho and their counterparts north of the Kootenai River, the Columbia Mountains, are considered a separate system in Canada, lying to the west of the huge Rocky Mountain Trench. This runs the length of British Columbia from its beginnings in the middle Flathead River valley in western Montana to the bank of the Liard River. The Rockies vary in width from 70 to 300 miles, also west of the Rocky Mountain Trench, farther north and facing the Muskwa Range across the trench, are the Stikine Ranges and Omineca Mountains of the Interior Mountains system of British Columbia. A small area east of Prince George, British Columbia on the side of the Trench. In Canada geographers define three main groups of ranges, the Continental Ranges, Hart Ranges and Muskwa Ranges, the Muskwa and Hart Ranges together comprise what is known as the Northern Rockies. The western edge of the Rockies includes ranges such as the Wasatch near Salt Lake City, the Great Basin and Columbia River Plateau separate these sub-ranges from distinct ranges further to the west, most prominent among which are the Sierra Nevada, Cascade Range and Coast Mountains. The Rocky Mountain System within the United States is a United States physiographic region, the Rocky Mountains are notable for containing the highest peaks in central North America. The ranges highest peak is Mount Elbert located in Colorado at 14,440 feet above sea level, Mount Robson in British Columbia, at 12,972 feet, is the highest peak in the Canadian Rockies. The Continental Divide of the Americas is located in the Rocky Mountains, triple Divide Peak in Glacier National Park is so named because water that falls on the mountain reaches not only the Atlantic and Pacific, but Hudson Bay as well. Farther north in Alberta, the Athabasca and other rivers feed the basin of the Mackenzie River, see Rivers of the Rocky Mountains for a list of rivers. Human population is not very dense in the Rocky Mountains, with an average of four people per square kilometer, however, the human population grew rapidly in the Rocky Mountain states between 1950 and 1990. The 40-year statewide increases in range from 35% in Montana to about 150% in Utah
3.
Plain
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In geography, a plain is a flat, sweeping landmass that generally does not change much in elevation. Plains occur as lowlands along the bottoms of valleys or on the doorsteps of mountains, as coastal plains, and as plateaus or uplands. In a valley, a plain is enclosed on two sides but in other cases a plain may be delineated by a complete or partial ring of hills, where a geological region contains more than one plain, they may be connected by a pass. Coastal plains would mostly rise from sea level until they run into elevated features such as mountains or plateaus, plains are one of the major landforms on earth, where they are present on all continents, and would cover more than one-third of the world’s land area. Plains may have formed from flowing lava, deposited by water, ice, wind, or formed by erosion by these agents from hills. Plains would generally be under the grassland, steppe, savannah or tundra biomes, in a few instances, deserts and rainforests can also be plains. Structural plains are relatively undisturbed horizontal surfaces of the Earth and they are structurally depressed areas of the world that make up some of the most extensive natural lowlands on the Earths surface. Erosional plains have been leveled by various agents of such as running water, rivers, wind and glacier which wear out the rugged surface. Plain resulting from the action of these agents of denudation are called peneplains while plains formed from wind action are called pediplains, depositional plains formed by the deposition of materials brought by various agents of transportation such as rivers, wind, waves, and glaciers. Their fertility and economic relevance depend greatly on the types of sediments that are laid down, flood plain, adjacent to a stream, river, lake or wetland that experiences occasional or periodic flooding. Scroll plain, a plain through which a river meanders with a low gradient. Lacustrine plain, a plain that originally formed in a lacustrine environment, lava plain, formed by sheets of flowing lava. Glacial plains, formed by the movement of glaciers under the force of gravity, Sandur, sandar consist mainly of stratified gravel and sand. Till plain, a plain of glacial till that forms when a sheet of ice becomes detached from the body of a glacier. Till plains are composed of unsorted material of all sizes, abyssal plain, a flat or very gently sloping area of the deep ocean basin. Planitia, the Latin word for plain, is used in the naming of plains on extraterrestrial objects, such as Hellas Planitia on Mars or Sedna Planitia on Venus
4.
Bureau of Land Management
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President Harry S. Truman created the BLM in 1946 by combining two existing agencies, the General Land Office and the Grazing Service. Most BLM public lands are located in these 12 western states, Alaska, Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming. The mission of the BLM is to sustain the health, diversity, originally BLM holdings were described as land nobody wanted because homesteaders had passed them by. All the same, ranchers hold nearly 18,000 permits, the agency manages 221 wilderness areas,23 national monuments and some 636 other protected areas as part of the National Landscape Conservation System totaling about 30 million acres. There are more than 63,000 oil and gas wells on BLM public lands, total energy leases generated approximately $5.4 billion in 2013, an amount divided among the Treasury, the states, and Native American groups. The BLMs roots go back to the Land Ordinance of 1785 and these laws provided for the survey and settlement of the lands that the original 13 colonies ceded to the federal government after the American Revolution. As additional lands were acquired by the United States from Spain, France and other countries, the United States Congress directed that they be explored, surveyed, during the Revolutionary War, military bounty land was promised to soldiers who fought for the colonies. After the war, the Treaty of Paris of 1783, signed by the United States, England, France, in the 1780s, other states relinquished their own claims to land in modern-day Ohio. By this time, the United States needed revenue to function, Land was sold so that the government would have money to survive. In order to sell the land, surveys needed to be conducted, the Land Ordinance of 1785 instructed a geographer to oversee this work as undertaken by a group of surveyors. The first years of surveying were completed by trial and error, once the territory of Ohio had been surveyed, in 1812, Congress established the General Land Office as part of the Department of the Treasury to oversee the disposition of these federal lands. By the early 1800s, promised bounty land claims were finally fulfilled, over the years, other bounty land and homestead laws were enacted to dispose of federal land. Several different types of patents existed and these include cash entry, credit, homestead, Indian, military warrants, mineral certificates, private land claims, railroads, state selections, swamps, town sites, and town lots. A system of land offices spread throughout the territories, patenting land that was surveyed via the corresponding Office of the Surveyor General of a particular territory. This pattern gradually spread across the entire United States, the laws that spurred this system with the exception of the General Mining Law of 1872 and the Desert Land Act of 1877 have since been repealed or superseded. The Mineral Leasing Act of 1920 allowed leasing, exploration, and production of selected commodities, such as coal, oil, gas, the Taylor Grazing Act of 1934 established the United States Grazing Service to manage the public rangelands by establishment of advisory boards that set grazing fees. The Oregon and California Revested Lands Sustained Yield Management Act of 1937, commonly referred as the O&C Act, in 1946, the Grazing Service was merged with the General Land Office to form the Bureau of Land Management within the Department of the Interior. It took several years for new agency to integrate and reorganize
5.
Montana
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Montana /mɒnˈtænə/ is a state in the Western region of the United States. The states name is derived from the Spanish word montaña, Montana has several nicknames, although none official, including Big Sky Country and The Treasure State, and slogans that include Land of the Shining Mountains and more recently The Last Best Place. Montana has a 545-mile border with three Canadian provinces, British Columbia, Alberta, and Saskatchewan, the state to do so. It also borders North Dakota and South Dakota to the east, Wyoming to the south, Montana is ranked 4th in size, but 44th in population and 48th in population density of the 50 United States. The western third of Montana contains numerous mountain ranges, smaller island ranges are found throughout the state. In total,77 named ranges are part of the Rocky Mountains, the eastern half of Montana is characterized by western prairie terrain and badlands. The economy is based on agriculture, including ranching and cereal grain farming. Other significant economic activities include oil, gas, coal and hard rock mining, lumber, the health care, service, and government sectors also are significant to the states economy. Millions of tourists annually visit Glacier National Park, the Little Bighorn Battlefield National Monument, the name Montana comes from the Spanish word Montaña and the Latin word Montana, meaning mountain, or more broadly, mountainous country. Montaña del Norte was the name given by early Spanish explorers to the mountainous region of the west. The name was changed by Representatives Henry Wilson and Benjamin F. Harding, when Ashley presented a bill to establish a temporary government in 1864 for a new territory to be carved out of Idaho, he again chose Montana Territory. This time Rep. Samuel Cox, also of Ohio, objected to the name, Cox complained that the name was a misnomer given most of the territory was not mountainous and that a Native American name would be more appropriate than a Spanish one. Other names such as Shoshone were suggested, but it was decided that the Committee on Territories could name it whatever they wanted, with an area of 147,040 square miles, Montana is slightly larger than Japan. It is the fourth largest state in the United States after Alaska, Texas, and California, the largest landlocked U. S. state, and the worlds 56th largest national state/province subdivision. To the north, Montana shares a 545-mile border with three Canadian provinces, British Columbia, Alberta, and Saskatchewan, the state to do so. It borders North Dakota and South Dakota to the east, Wyoming to the south, the states topography is roughly defined by the Continental Divide, which splits much of the state into distinct eastern and western regions. Most of Montanas 100 or more named mountain ranges are in the western half. The Absaroka and Beartooth ranges in the states south-central part are part of the Central Rocky Mountains
6.
Gulf of Mexico
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The Gulf of Mexico is an ocean basin largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. The U. S. states of Alabama, Florida, Louisiana, Mississippi and Texas border the Gulf on the north, Atlantic and Pacific coasts, or sometimes the south coast, in juxtaposition to the Great Lakes region being the north coast. One of the seven main areas is the Gulf of Mexico basin. The Gulf of Mexico formed approximately 300 million years ago as a result of plate tectonics, the Gulfs basin is roughly oval and is approximately 810 nautical miles wide and floored by sedimentary rocks and recent sediments. It is connected to part of the Atlantic Ocean through the Florida Straits between the U. S. and Cuba, and with the Caribbean Sea via the Yucatan Channel between Mexico and Cuba, with the narrow connection to the Atlantic, the Gulf experiences very small tidal ranges. The size of the Gulf basin is approximately 1.6 million km2, almost half of the basin is shallow continental shelf waters. The basin contains a volume of roughly 2,500 quadrillion liters, the consensus among geologists who have studied the geology of the Gulf of Mexico, is that prior to the Late Triassic, the Gulf of Mexico did not exist. It was created by the collision of plates that formed Pangea. As interpreted by Roy Van Arsdale and Randel T. Cox, geologists and other Earth scientists agree in general that the present Gulf of Mexico basin originated in Late Triassic time as the result of rifting within Pangea. The rifting was associated with zones of weakness within Pangea, including sutures where the Laurentia, South American, first, there was a Late Triassic-Early Jurassic phase of rifting during which rift valleys formed and filled with continental red beds. Second, as rifting progressed through Early and Middle Jurassic time and it was at this time that tectonics first created a connection to the Pacific Ocean across central Mexico and later eastward to the Atlantic Ocean. This flooded the basin created by rifting and crustal thinning to create the Gulf of Mexico. While the Gulf of Mexico was a basin, the subsiding transitional crust was blanketed by the widespread deposition of Louann Salt. Initially, during the Late Jurassic, continued rifting widened the Gulf of Mexico and progressed to the point that sea-floor spreading, at this point, sufficient circulation with the Atlantic Ocean was established that the deposition of Louann Salt ceased. During the Late Jurassic through Early Cretaceous, the occupied by the Gulf of Mexico experienced a period of cooling. The subsidence was the result of a combination of stretching, cooling. Initially, the combination of stretching and cooling caused about 5–7 km of tectonic subsidence of the central thin transitional
7.
Hail
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Hail is a form of solid precipitation. It is distinct from ice pellets, though the two are often confused and it consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets falls generally in cold weather while hail growth is inhibited during cold surface temperatures. Unlike graupel, which is made of rime, and ice pellets, the METAR reporting code for hail 5 mm or greater is GR, while smaller hailstones and graupel are coded GS. Hail is possible within most thunderstorms as it is produced by cumulonimbus, Hail formation requires environments of strong, upward motion of air with the parent thunderstorm and lowered heights of the freezing level. In the mid-latitudes, hail forms near the interiors of continents, while in the tropics, there are methods available to detect hail-producing thunderstorms using weather satellites and weather radar imagery. Severe weather warnings are issued for hail when the stones reach a size, as it can cause serious damage to human-made structures and, most commonly. Any thunderstorm which produces hail that reaches the ground is known as a hailstorm, Hail has a diameter of 5 millimetres or more. Hailstones can grow to 15 centimetres and weigh more than 0.5 kilograms, unlike ice pellets, hailstones are layered and can be irregular and clumped together. Although the diameter of hail is varied, in the United States, stones larger than 2 cm are usually considered large enough to cause damage. The Meteorological Service of Canada issues severe thunderstorm warnings when hail that size or above is expected, the US National Weather Service has a 2.5 cm or greater in diameter threshold, effective January 2010, an increase over the previous threshold of ¾-inch hail. Other countries have different thresholds according local sensitivity to hail, for grape growing areas could be adversely impacted by smaller hailstones. Hailstones can be large or very small, depending on how strong the updraft is. These types of strong updrafts can also indicate the presence of a tornado, the growth rate is maximized where air is near a temperature of −13 °C. Like other precipitation in clouds, hail begins as water droplets. As the droplets rise and the temperature goes below freezing, they become supercooled water, a cross-section through a large hailstone shows an onion-like structure. This means the hailstone is made of thick and translucent layers, alternating layers that are thin, white. Former theory suggested that hailstones were subjected to multiple descents and ascents, falling into a zone of humidity and this up and down motion was thought to be responsible for the successive layers of the hailstone
8.
Thunderstorm
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Thunderstorms occur in association with a type of cloud known as a cumulonimbus. They are usually accompanied by winds, heavy rain, and sometimes snow, sleet, hail, or, in contrast. Thunderstorms may line up in a series or become a rainband, strong or severe thunderstorms, known as supercells, rotate as do cyclones. Thunderstorms result from the upward movement of warm, moist air. As the warm, moist air moves upward, it cools, condenses, as the rising air reaches its dew point temperature, water vapor condenses into water droplets or ice, reducing pressure locally within the thunderstorm cell. Any precipitation falls the long distance through the clouds towards the Earths surface, as the droplets fall, they collide with other droplets and become larger. Thunderstorms can form and develop in any location but most frequently within the mid-latitude. Thunderstorms are responsible for the development and formation of many weather phenomena. Thunderstorms, and the phenomena that occur along them, pose great hazards. Damage that results from thunderstorms is mainly inflicted by downburst winds, large hailstones, stronger thunderstorm cells are capable of producing tornadoes and waterspouts. There are four types of thunderstorms, single-cell, multi-cell cluster, multi-cell lines, supercell thunderstorms are the strongest and the most associated with severe weather phenomena. Mesoscale convective systems formed by vertical wind shear within the tropics and subtropics can be responsible for the development of hurricanes. Dry thunderstorms, with no precipitation, can cause the outbreak of wildfires from the heat generated from the lightning that accompanies them. Several means are used to study thunderstorms, weather radar, weather stations, past civilizations held various myths concerning thunderstorms and their development as late as the 18th century. Beyond the Earths atmosphere, thunderstorms have also observed on the planets of Jupiter, Saturn, Neptune. Warm air has a lower density than air, so warmer air rises upwards. Clouds form as relatively warmer air, carrying moisture, rises within cooler air, the moist air rises, and, as it does so, it cools and some of the water vapor in that rising air condenses. If enough instability is present in the atmosphere, this process will continue long enough for cumulonimbus clouds to form and produce lightning, Meteorological indices such as convective available potential energy and the lifted index can be used to assist in determining potential upward vertical development of clouds
9.
Tornado
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A tornado is a rapidly rotating column of air that spins while in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. Most tornadoes have wind speeds less than 110 miles per hour, are about 250 feet across, the most extreme tornadoes can attain wind speeds of more than 300 miles per hour, are more than two miles in diameter, and stay on the ground for dozens of miles. Various types of tornadoes include the multiple vortex tornado, landspout and waterspout, waterspouts are characterized by a spiraling funnel-shaped wind current, connecting to a large cumulus or cumulonimbus cloud. They are generally classified as non-supercellular tornadoes that develop over bodies of water and these spiraling columns of air frequently develop in tropical areas close to the equator, and are less common at high latitudes. Other tornado-like phenomena that exist in nature include the gustnado, dust devil, fire whirls, downbursts are frequently confused with tornadoes, though their action is dissimilar. Tornadoes have been observed and documented on every continent except Antarctica, however, the vast majority of tornadoes occur in the Tornado Alley region of the United States, although they can occur nearly anywhere in North America. There are several scales for rating the strength of tornadoes, the Fujita scale rates tornadoes by damage caused and has been replaced in some countries by the updated Enhanced Fujita Scale. An F0 or EF0 tornado, the weakest category, damages trees, an F5 or EF5 tornado, the strongest category, rips buildings off their foundations and can deform large skyscrapers. The similar TORRO scale ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes, Doppler radar data, photogrammetry, and ground swirl patterns may also be analyzed to determine intensity and assign a rating. The word tornado is a form of the Spanish word tronada. This in turn was taken from the Latin tonare, meaning to thunder and it most likely reached its present form through a combination of the Spanish tronada and tornar, however, this may be a folk etymology. A tornado is also referred to as a twister, and is also sometimes referred to by the old-fashioned colloquial term cyclone. The term cyclone is used as a synonym for tornado in the often-aired 1939 film The Wizard of Oz, the term twister is also used in that film, along with being the title of the 1996 tornado-related film Twister. A tornado is a rotating column of air, in contact with the ground, either pendant from a cumuliform cloud or underneath a cumuliform cloud. For a vortex to be classified as a tornado, it must be in contact with both the ground and the cloud base. Scientists have not yet created a definition of the word, for example. Tornado refers to the vortex of wind, not the condensation cloud and this results in the formation of a visible funnel cloud or condensation funnel. There is some disagreement over the definition of cloud and condensation funnel
