Rocky Mountains

The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in a straight-line distance from the northernmost part of Western Canada, to New Mexico in the Southwestern United States. Depending on differing definitions between Canada and the U.S., its northern terminus is located either in northern British Columbia's Terminal Range south of the Liard River and east of the Trench, or in the northeastern foothills of the Brooks Range/British Mountains that face the Beaufort Sea coasts between the Canning River and the Firth River across the Alaska–Yukon border. Public parks and forest lands protect much of the mountain range, and they are popular tourist destinations, especially for hiking, camping, mountaineering, fishing, hunting, mountain biking, snowmobiling, skiing, and snowboarding.

Etymology

thumb|The [[Santa Fe Mountains at the southern end of the Rockies as seen from the Sandia Crest in New Mexico]]

thumb|right|The summits of the [[Teton Range in Wyoming]]

The name of the mountains is a calque of an Algonquian name, specifically the Plains Cree (originally transcribed ), literally "rocky mountain / alp"; its French form "" first attested (and thus first to European knowledge) in Jacques Legardeur de Saint-Pierre's journal in 1752. Another name given to the place by the Cree is .

Geography

The Rocky Mountains are the easternmost portion of the expansive North American Cordillera. They are often defined as a network stretching from the Liard River in British Columbia

Central ranges of the Rockies include the La Sal Range along the Utah-Colorado border, the Abajo Mountains and Henry Mountains of Southeastern Utah, the Uinta Range of Utah and Wyoming, and the Teton Range of Wyoming and Idaho.

The western edge of the Rockies includes ranges such as the Wasatch near Salt Lake City, the San Juan Mountains of New Mexico and Colorado, the Bitterroots along the Idaho-Montana border, and the Sawtooths in central Idaho. The Great Basin and Columbia River Plateau separate these subranges from distinct ranges further to the west. In Canada, the western edge of the Rockies is formed by the huge Rocky Mountain Trench, which runs the length of British Columbia from its beginning as the Kechika Valley on the south bank of the Liard River, to the middle Lake Koocanusa valley in northwestern Montana.

The Canadian Rockies are defined by Canadian geographers as everything south of the Liard River and east of the Rocky Mountain Trench, and do not extend into Yukon, Northwest Territories or central British Columbia. They are divided into three main groups: the Muskwa Ranges, Hart Ranges (collectively called the Northern Rockies) and Continental Ranges. Other more northerly mountain ranges of the eastern Canadian Cordillera continue beyond the Liard River valley, including the Selwyn, Mackenzie and Richardson Mountains in Yukon as well as the British Mountains/Brooks Range in Alaska, but those are not officially recognized as part of the Rockies by the Geological Survey of Canada, although the Geological Society of America definition does consider them parts of the Rocky Mountains system as the "Arctic Rockies".

The Continental Divide of the Americas is in the Rocky Mountains and designates the line at which waters flow either to the Atlantic or Pacific Oceans. Triple Divide Peak () in Glacier National Park is so named because water falling 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, which has its outlet on the Beaufort Sea of the Arctic Ocean.

Human population is not very dense in the Rockies, with an average of four people per square kilometer and few cities with over 50,000 people. However, the human population grew rapidly in the Rocky Mountain states between 1950 and 1990. The forty-year statewide increases in population range from 35% in Montana to about 150% in Utah and Colorado. The populations of several mountain towns and communities have doubled in the forty years 1972–2012. Jackson, Wyoming, increased 260%, from 1,244 to 4,472 residents, in those forty years.

thumb|right|Glaciers, such as [[Jackson Glacier in Glacier National Park, Montana, as shown here, have dramatically shaped the Rocky Mountains.]]

In the southern Rockies, near present-day Colorado, these ancestral rocks were disturbed by mountain building approximately 300 million years ago, during the Pennsylvanian. This mountain-building produced the Ancestral Rocky Mountains. They consisted largely of Precambrian metamorphic rock forced upward through layers of the limestone laid down in the shallow sea. The mountains eroded throughout the late Paleozoic and early Mesozoic, leaving extensive deposits of sedimentary rock.

Terranes began colliding with the western edge of North America in the Mississippian (approximately 350 million years ago), causing the Antler orogeny. For 270 million years, the focus of the effects of plate collisions were near the edge of the North American Plate boundary, far to the west of the Rocky Mountain region.

The current Rocky Mountains arose in the Laramide orogeny from between 80 million and 55 million years ago. the rug bunches up and forms wrinkles (mountains). In Canada, the terranes and subduction are the foot pushing the rug, the ancestral rocks are the rug, and the Canadian Shield in the middle of the continent is the hardwood floor.

Some researchers have proposed that aspects of Rocky Mountain uplift and deformation are better explained by a “hit-and-run” tectonic collision model, in which oblique and transient plate interactions distributed deformation far inland, rather than through long-lived shallow-angle subduction alone.

thumb|left|Tilted slabs of sedimentary rock in [[Roxborough State Park near Denver]]

The current southern Rockies were forced upwards through the layers of Pennsylvanian and Permian sedimentary remnants of the Ancestral Rocky Mountains. Such sedimentary remnants were often tilted at steep angles along the flanks of the modern range; they are now visible in many places throughout the Rockies, and are shown along the Dakota Hogback, an early Cretaceous sandstone formation running along the eastern flank of the modern Rockies.

Just after the Laramide orogeny, the Rockies were like Tibet: a high plateau, probably above sea level. In the last 60 million years, erosion stripped away the high rocks, revealing the ancestral rocks beneath, and forming the current landscape of the Rockies.

All of these geological processes exposed a complex set of rocks at the surface. For example, volcanic rock from the Paleogene and Neogene periods (66 million – 2.6 million years ago) occurs in the San Juan Mountains and in other areas. Millennia of severe erosion in the Wyoming Basin transformed intermountain basins into a relatively flat terrain. The Tetons and other north-central ranges contain folded and faulted rocks of Paleozoic and Mesozoic age draped above cores of Proterozoic and Archean igneous and metamorphic rocks ranging in age from 1.2 billion (e.g., Tetons) to more than 3.3 billion years (Beartooth Mountains).

Ecology and climate

There are a wide range of environmental factors in the Rocky Mountains. The Rockies range in latitude between the Liard River in British Columbia (at 59° N) and the Rio Grande in New Mexico (at 35° N). Prairie occurs at or below , while the highest peak in the range is Mount Elbert at . Precipitation ranges from per year in the southern valleys to per year locally in the northern peaks. Average January temperatures can range from in Prince George, British Columbia, to in Trinidad, Colorado.

thumb|right|[[Bighorn sheep (such as this lamb in Alberta) have declined dramatically since European-American settlement of the mountains]]

The U.S. Geological Survey defines ten forested zones in the Rockies. Zones in more southern, warmer, or drier areas are defined by the presence of pinyon pines/junipers, ponderosa pines, or oaks mixed with pines. In more northern, colder, or wetter areas, zones are defined by Douglas firs, Cascadian species (such as western hemlock), lodgepole pines/quaking aspens, or firs mixed with spruce. Near tree-line, zones can consist of white pines (such as whitebark pine or bristlecone pine); or a mixture of white pine, fir, and spruce that appear as shrub-like krummholz. Finally, rivers and canyons can create a unique forest zone in more arid parts of the mountain range. North America's largest herds of elk are in the Alberta–British Columbia foothills forests.

The status of most species in the Rocky Mountains is unknown, due to incomplete information. European-American settlement of the mountains has adversely impacted native species. Examples of some species that have declined include western toads, greenback cutthroat trout, white sturgeon, white-tailed ptarmigan, trumpeter swan, and bighorn sheep.

In the U.S. portion of the mountain range, apex predators such as grizzly bears and wolf packs had been extirpated from their original ranges, but have partially recovered due to conservation measures and reintroduction. Other recovering species include the bald eagle and the peregrine falcon. In 1610, the Spanish founded the city of Santa Fe, the oldest continuous seat of government in the United States, at the foot of the Rockies in present-day New Mexico. The introduction of the horse, metal tools, rifles, new diseases, and different cultures profoundly changed the Native American cultures. Native American populations were extirpated from most of their historical ranges by disease, warfare, habitat loss (eradication of the bison), and continued assaults on their culture.

thumb|upright|Sir Alexander Mackenzie in 1800

Sir Alexander Mackenzie (1764 – March 11, 1820) became the first European to cross the Rocky Mountains in 1793. He found the upper reaches of the Fraser River and reached the Pacific coast of what is now Canada on July 20 of that year, completing the first recorded transcontinental crossing of North America north of Mexico. He arrived at Bella Coola, British Columbia, where he first reached saltwater at South Bentinck Arm, an inlet of the Pacific Ocean.

The Lewis and Clark Expedition (1804–1806) was the first scientific reconnaissance of the Rocky Mountains. Specimens were collected for contemporary botanists, zoologists, and geologists. The expedition was said to have paved the way to (and through) the Rocky Mountains for European-Americans from the East, although Lewis and Clark met at least 11 European-American mountain men during their travels. These posts served as bases for most European activity in the Canadian Rockies in the early 19th century. Among the most notable are the expeditions of David Thompson, who followed the Columbia River to the Pacific Ocean. On his 1811 expedition, he camped at the junction of the Columbia River and the Snake River and erected a pole and notice claiming the area for the United Kingdom and stating the intention of the North West Company to build a fort at the site.

By the Anglo-American Convention of 1818, which established the 49th parallel north as the international boundary west from Lake of the Woods to the "Stony Mountains", the UK and the US agreed to what has since been described as "joint occupancy" of lands further west to the Pacific Ocean. Resolution of the territorial and treaty issues, the Oregon dispute, was deferred until a later time.

In 1819, Spain ceded their rights north of the 42nd Parallel to the United States, though these rights did not include possession and also included obligations to Britain and Russia concerning their claims in the same region.

Settlement

thumb|right|[[Aspen, Colorado silver mining in 1898]]

After 1802, fur traders and explorers ushered in the first widespread American presence in the Rockies south of the 49th parallel. The more famous of these include William Henry Ashley, Jim Bridger, Kit Carson, John Colter, Thomas Fitzpatrick, Andrew Henry, and Jedediah Smith. On July 24, 1832, Benjamin Bonneville led the first wagon train across the Rocky Mountains by using South Pass in the present State of Wyoming.

thumb|right|The [[Saltair (Utah)|Saltair Pavilion on the Great Salt Lake in 1900]]

Thousands passed through the Rocky Mountains on the Oregon Trail beginning in the 1840s. The Mormons began settling near the Great Salt Lake in 1847 and proceeded to extend settlements along the Wasatch range and into eastern Idaho throughout the subsequent decades. From 1859 to 1864, gold was discovered in Colorado, Idaho, Montana, and British Columbia, sparking several gold rushes bringing thousands of prospectors and miners to explore every mountain and canyon and to create the Rocky Mountains' first major industry. The Idaho gold rush alone produced more gold than the California and Alaska gold rushes combined and was important in the financing of the Union Army during the American Civil War. The transcontinental railroad was completed in 1869, and Yellowstone National Park was established as the world's first national park in 1872. Meanwhile, a transcontinental railroad in Canada was originally promised in 1871. Though political complications pushed its completion to 1885, the Canadian Pacific Railway eventually followed the Kicking Horse and Rogers Passes to the Pacific Ocean. Canadian railway officials also convinced Parliament to set aside vast areas of the Canadian Rockies as Jasper, Banff, Yoho, and Waterton Lakes National Parks, laying the foundation for a tourism industry which thrives to this day. Glacier National Park (MT) was established with a similar relationship to tourism promotions by the Great Northern Railway. While settlers filled the valleys and mining towns, conservation and preservation ethics began to take hold. U.S. President Benjamin Harrison established several forest reserves in the Rocky Mountains in 1891–1892. In 1905, U.S. President Theodore Roosevelt extended the Medicine Bow Forest Reserve to include the area now managed as Rocky Mountain National Park. Economic development began to center on mining, forestry, agriculture, and recreation, as well as on the service industries that support them. Tents and camps became ranches and farms, forts and train stations became towns, and some towns became cities.

The Rocky Mountains contain several sedimentary basins that are rich in coalbed methane. Coalbed methane is natural gas that arises from coal, either through bacterial action or through exposure to high temperature. Coalbed methane supplies 7 percent of the natural gas used in the U.S. The largest coalbed methane sources in the Rocky Mountains are in the San Juan Basin in New Mexico and Colorado and the Powder River Basin in Wyoming. These two basins are estimated to contain 38 trillion cubic feet of gas. Coalbed methane can be recovered by dewatering the coal bed, and separating the gas from the water; or injecting water to fracture the coal to release the gas (so-called hydraulic fracturing).

Agriculture and forestry are major industries. Agriculture includes dryland and irrigated farming and livestock grazing. Livestock are frequently moved between high-elevation summer pastures and low-elevation winter pastures, a practice known as transhumance. In the summer season, examples of tourist attractions are:

In the United States:

Yellowstone National Park
Glacier National Park
Grand Teton National Park
Rocky Mountain National Park
Great Sand Dunes National Park and Preserve
Sawtooth National Recreation Area
Flathead Lake

In Canada, the mountain range contains these national parks:

Banff National Park
Jasper National Park
Kootenay National Park
Waterton Lakes National Park
Yoho National Park

Glacier National Park in Montana and Waterton Lakes National Park in Alberta border each other and are collectively known as Waterton-Glacier International Peace Park.

In the winter, skiing and snowboarding are the main attractions, with dozens of Rocky Mountain ski areas and resorts.

The adjacent Columbia Mountains in British Columbia contain major resorts such as Panorama and Kicking Horse, as well as Mount Revelstoke National Park and Glacier National Park.

There are numerous provincial parks in the British Columbia Rockies, the largest and most notable being Mount Assiniboine Provincial Park, Mount Robson Provincial Park, Northern Rocky Mountains Provincial Park, Kwadacha Wilderness Provincial Park, Stone Mountain Provincial Park and Muncho Lake Provincial Park.

John Denver wrote the song "Rocky Mountain High" in 1972. The song is one of the two official state songs of Colorado.

Hazards

Encountering bears or mountain lions (cougars) is a concern in the Rocky Mountains. There are other concerns as well, including bugs, wildfires, adverse snow conditions and nighttime cold temperatures.

Importantly, there have been notable incidents in the Rocky Mountains, including accidental deaths, due to falls from steep cliffs (a misstep could be fatal in this class 4/5 terrain) and due to falling rocks, over the years, including 1993, 2007 (involving an experienced NOLS leader), 2015 and 2018. Other incidents include a seriously injured backpacker being airlifted near SquareTop Mountain in 2005, and a fatal hiker incident (from an apparent accidental fall) in 2006 that involved state search and rescue. The U.S. Forest Service does not offer updated aggregated records on the official number of fatalities in the Rocky Mountains.

References

External links

Colorado Rockies Forests ecoregion images at bioimages.vanderbilt.edu (slow modem version)
North Central Rockies Forests ecoregion images at bioimages.vanderbilt.edu (slow modem version)
South Central Rockies Forests ecoregion images at bioimages.vanderbilt.edu (slow modem version)
Sunset on the Top of the Rocky Mountains, CO, Historical Society of Pennsylvania