Rocky Mountains

• 1. Introduction

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  The Rocky Mountains run 3,000 miles in a straight line, from the northernmost part of Western Canada all the way down to New Mexico. They are the largest mountain system in North America, a collective network of dozens of distinct subranges. Yet for all their size, the Rockies have never held a dense human population. Today an average of just four people occupy each square kilometer, and few cities exceed 50,000 residents. So how did a range this vast end up so empty? What forces piled crust on top of crust to build it, and who came looking for what it held? The name itself is a clue. It is a calque of an Algonquian word, the Plains Cree asinîwaciy, meaning literally rocky mountain. The questions that follow trace how the Rockies were raised, settled, mined, and finally set aside.

• 2. How The Range Rose

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  The current Rocky Mountains arose during the Laramide orogeny, between 80 million and 55 million years ago. A number of plates began sliding underneath the North American plate at a shallow angle, producing a broad belt of mountains running down western North America. For the Canadian Rockies, geologists compare the process to pushing a rug across a hardwood floor. The rug bunches up into wrinkles. The terranes and subduction are the foot, the ancestral rocks are the rug, and the Canadian Shield is the floor.

  The Farallon Plate dove at an unusually shallow angle below the North American Plate further south. This low angle moved the focus of melting and mountain building far inland, well past the normal 200 to 300 miles. Scientists hypothesize the shallow angle increased friction with the thick continental mass above it. Tremendous thrusts piled sheets of crust on top of each other, building the broad, high range.

  Some researchers favor a different account. They propose a hit-and-run tectonic collision model, in which oblique and transient plate interactions distributed deformation far inland, rather than long-lived shallow-angle subduction alone. Related alternatives to traditional Cordilleran models were discussed at a Geological Society of America Penrose Conference held in Idaho.

  The rocks themselves are far older than the uplift. The oldest is Precambrian metamorphic rock forming the core of the continent, and there is Precambrian sedimentary argillite dating back 1.7 billion years. The Tetons drape Paleozoic and Mesozoic rock over cores ranging from 1.2 billion years to more than 3.3 billion years in the Beartooth Mountains.

• 3. A Continent Of Subranges

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  Mount Elbert in Colorado rises 14,440 feet above sea level, the highest peak in the entire range. The Rockies hold the highest peaks in central North America, and most of the highest summits sit in Colorado, a state with an average elevation of 6,800 feet. In British Columbia, Mount Robson reaches 12,972 feet, the highest peak in the Canadian Rockies.

  The eastern edge rises dramatically above the Interior Plains. It includes the Sangre de Cristo Mountains, the Front Range of Colorado, the Wind River Range and Big Horn Mountains of Wyoming, and the Black Hills of South Dakota. Central ranges include the Uinta Range of Utah and Wyoming and the Teton Range of Wyoming and Idaho. The western edge holds the Wasatch near Salt Lake City, the San Juan Mountains, and the Sawtooths in central Idaho.

  The Rocky Mountain Trench forms the western edge in Canada, a huge feature running the length of British Columbia. Canadian geographers define the Canadian Rockies as everything south of the Liard River and east of the Trench. They divide into the Muskwa Ranges, the Hart Ranges, and the Continental Ranges. Ranges beyond the Liard valley, such as the British Mountains in Alaska, are not officially recognized as Rockies by the Geological Survey of Canada, though the Geological Society of America counts them as the Arctic Rockies.

  The Continental Divide of the Americas runs through the range, marking where waters flow toward either the Atlantic or the Pacific. Triple Divide Peak, at 8,020 feet in Glacier National Park, sends water to a third destination as well: Hudson Bay.

• 4. Tundra, Forest, And Fauna

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  Precipitation ranges from 10 inches per year in the southern valleys to 60 inches per year locally in the northern peaks. The range stretches in latitude from the Liard River at 59 degrees north to the Rio Grande at 35 degrees north. Average January temperatures can run from 20 degrees Fahrenheit in Prince George, British Columbia, to 43 degrees in Trinidad, Colorado. There is no single ecosystem for the whole range.

  Ecologists divide the Rockies into biotic zones, each defined by whether it can support trees and by indicator species. The Plains and the Alpine tundra support no trees. Alpine tundra sits above the tree-line, which varies from 12,000 feet in New Mexico to 2,500 feet near the Yukon. The U.S. Geological Survey defines ten forested zones, ranging from pinyon pines and junipers in warmer, drier areas to white pines that appear as shrub-like krummholz near the tree-line.

  North America's largest herds of elk roam the Alberta and British Columbia foothills forests. The range is habitat for wolves, moose, pronghorn, mountain goats, bighorn sheep, grizzly bears, lynxes, cougars, and wolverines. European-American settlement adversely impacted native species, and the status of most remains unknown due to incomplete information. Western toads, greenback cutthroat trout, and bighorn sheep all declined.

  Some species have come back. Grizzly bears and wolf packs were extirpated from their original U.S. ranges, then partially recovered through conservation and reintroduction. The bald eagle and the peregrine falcon are recovering too.

• 5. First Peoples And First Crossings

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  Along the crest of the Continental Divide in Colorado, Native Americans built rock walls for driving game that date back 5,400 to 5,800 years. Since the last great ice age the Rockies were home to peoples including the Apache, Arapaho, Blackfoot, Cheyenne, Crow Nation, Shoshone, Sioux, Ute, and Kutenai. Paleo-Indians hunted the now-extinct mammoth and an ancient bison 20 percent larger than the modern animal. They likely moved to the plains in fall and winter, and to the mountains in spring and summer for fish, deer, elk, roots, and berries.

  The Spanish explorer Francisco Vazquez de Coronado marched into the region from the south in 1540, with soldiers and missionaries. In 1610 the Spanish founded Santa Fe, the oldest continuous seat of government in the United States, at the foot of the Rockies. The arrival of the horse, metal tools, rifles, new diseases, and different cultures profoundly changed Native American life. Populations were extirpated from most of their historical ranges by disease, warfare, and habitat loss.

  In 1739, French fur traders Pierre and Paul Mallet found a range at the headwaters of the Platte River that local tribes called the Rockies, becoming the first Europeans to report on it. Sir Alexander Mackenzie became the first European to cross the range in 1793. He reached the Pacific coast of what is now Canada on July 20, completing the first recorded transcontinental crossing of North America north of Mexico, arriving at Bella Coola.

  The Lewis and Clark Expedition, from 1804 to 1806, was the first scientific reconnaissance of the range, collecting specimens for botanists, zoologists, and geologists. The expedition was said to have paved the way through the Rockies, though Lewis and Clark met at least 11 European-American mountain men along the way.

• 6. Furs, Trails, And Treaties

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  Mountain men, primarily French, Spanish, and British, roamed the range from 1720 to 1800 seeking minerals and furs. The North West Company established Rocky Mountain House as a trading post in present-day Alberta in 1799, and the rival Hudson's Bay Company set up Acton House nearby. On his 1811 expedition, David Thompson camped at the junction of the Columbia and Snake Rivers and erected a pole claiming the area for the United Kingdom.

  The Anglo-American Convention of 1818 set the 49th parallel north as the boundary west to the Stony Mountains, with what was later called joint occupancy of lands further west. On the 24th of July 1832, Benjamin Bonneville led the first wagon train across the Rockies, using South Pass in present-day Wyoming. The more famous traders south of the 49th parallel included William Henry Ashley, Jim Bridger, Kit Carson, John Colter, and Jedediah Smith.

  In 1841, James Sinclair, Chief Factor of the Hudson's Bay Company, guided some 200 settlers from the Red River Colony west to bolster settlement around Fort Vancouver. The party crossed the Rockies near present-day Radium Hot Springs. Despite such efforts, Britain ceded all claim to Columbia District lands south of the 49th parallel in 1846, resolving the Oregon dispute through the Oregon Treaty.

  Thousands crossed on the Oregon Trail beginning in the 1840s. The Mormons began settling near the Great Salt Lake in 1847, extending along the Wasatch range into eastern Idaho. From 1859 to 1864, gold strikes in Colorado, Idaho, Montana, and British Columbia sparked rushes. The Idaho gold rush alone produced more gold than the California and Alaska rushes combined, helping finance the Union Army during the American Civil War.

• 7. Mines, Methane, And Parks

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  The Climax mine near Leadville, Colorado, was once the largest producer of molybdenum in the world, employing over 3,000 workers. Molybdenum goes into heat-resistant steel for cars and planes. The Rockies hold deposits of copper, gold, lead, silver, tungsten, and zinc, while the Wyoming Basin contains coal, natural gas, oil shale, and petroleum. The Coeur d'Alene mine of northern Idaho produces silver, lead, and zinc, and Canada's largest coal mines sit near Fernie and Sparwood, British Columbia.

  Abandoned mines and their tailings dot the landscape. Eighty years of zinc mining near Eagle River in north-central Colorado polluted the river and harmed algae, moss, and trout. An economic analysis found that cleaning up the river could yield 2.3 million dollars in additional recreation revenue. In 1983 the former mine owner was sued by the Colorado Attorney General for 4.8 million dollars in cleanup costs, and five years later ecological recovery was considerable.

  Coalbed methane supplies 7 percent of the natural gas used in the U.S. The San Juan Basin and the Powder River Basin together are estimated to hold 38 trillion cubic feet of gas. It can be recovered by dewatering the coal bed, or by injecting water to fracture the coal, a process known as hydraulic fracturing. Agriculture and forestry remain major industries, including the practice of transhumance, moving livestock between high summer and low winter pastures.

  Conservation grew alongside extraction. Yellowstone National Park was established in 1872 as the world's first national park. Railway officials convinced Canada's Parliament to set aside Jasper, Banff, Yoho, and Waterton Lakes National Parks. President Theodore Roosevelt extended the Medicine Bow Forest Reserve in 1905 to include what is now Rocky Mountain National Park.

• 8. The Draw And The Danger

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  John Denver wrote Rocky Mountain High in 1972, and the song became one of the two official state songs of Colorado. Every year the scenic areas draw millions of tourists who come to hike, camp, and engage in mountain sports. Summer visitors head for Yellowstone, Glacier, Grand Teton, and Great Sand Dunes National Park and Preserve, along with the Sawtooth National Recreation Area and Flathead Lake. In Canada the range holds Banff, Jasper, Kootenay, Waterton Lakes, and Yoho National Parks.

  Glacier National Park in Montana and Waterton Lakes National Park in Alberta border each other, together forming the Waterton-Glacier International Peace Park. In winter the draw shifts to skiing and snowboarding across dozens of resorts. The adjacent Columbia Mountains hold resorts such as Panorama and Kicking Horse, and British Columbia offers provincial parks including Mount Assiniboine, Mount Robson, and Muncho Lake.

  The same terrain that pulls visitors in carries real hazards. Bears and mountain lions are a concern, along with bugs, wildfires, adverse snow conditions, and nighttime cold. Notable incidents over the years have included accidental deaths from falls in class 4 and 5 terrain and from falling rocks, in 1993, 2007, 2015, and 2018. The 2007 case involved an experienced NOLS leader. The U.S. Forest Service does not offer updated aggregated records on the official number of fatalities in the Rockies, leaving the full toll of that empty, towering country uncounted.