Sierra Nevada (US)

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Sierra Nevada
The Sierra, The Sierras
Little Lakes Valley: typical eastside terrain
Country	United States
States	California, Nevada
Geology	batholith, igneous
Length	400 mi (644 km), North-South
Highest point	Mount Whitney
- coordinates	36°34′42.9″N, 118°17′31.2″W
- elevation	14,505 ft (4,421 m)
Position of Sierra Nevada inside California

The Sierra Nevada (Spanish for "Snowy Range") is a mountain range that is almost entirely in the eastern portion of the U.S. state of California. The range is also known as The Sierra and The Sierras.

Contents 1 Geography 2 Geology 3 Ecology 4 History 4.1 History of exploration 4.2 History of the name 5 Climate and meteorology 6 See also 7 References 8 External links

[edit] Geography

The Sierra Nevada stretches 400 miles (650 km), from Fredonyer Pass in the north to Tehachapi Pass in the south. It is bounded on the west by California's Central Valley, and on the east by the Great Basin.

In west-east cross section, the Sierra is shaped like a non-equilateral triangle: the elevation gradually increases eastward until the crest is reached, whereupon the elevation rapidly decreases, forming a steep escarpment. Thus, the crest runs principally along the eastern edge of the Sierra Nevada range. Rivers flowing west from the Sierra crest eventually drain into the Pacific Ocean, while rivers draining east flow into the Great Basin and do not reach any ocean. However, water from several streams and the Owens River is redirected to the city of Los Angeles (see Los Angeles Aqueduct). Thus, some east-flowing river water does make it to the Pacific Ocean.

There are several notable geographical features in the Sierra Nevada:

• Lake Tahoe is a large, clear freshwater lake in the northern Sierra Nevada, with an elevation of 6,225 feet (1,897 m) and an area of 191 square miles (489 km²). Lake Tahoe lies between the main Sierra and the Carson Range, a spur of the Sierra.
• Hetch Hetchy Valley, Yosemite Valley, Kings Canyon, Tehipite Valley and Kern Canyon are the most well-known of many beautiful, glacially-scoured canyons on the west side of the Sierra.
• Yosemite National Park is filled with stunning features, such as waterfalls and granite domes.
• Mount Whitney, at 14,505 feet (4,421 m), is the highest point in the contiguous United States.
• Groves of Giant Sequoias Sequoiadendron giganteum occur along a narrow band of altitude on the western side of the Sierra Nevada. Giant Sequoias are the most massive trees in the world.

The height of the mountains in the Sierra Nevada gradually increases from north to south. Between Fredonyer Pass and Lake Tahoe, the peaks range from 5,000 ft. (1,524 m) to 8,000 ft. (2,438 m).The crest near Lake Tahoe is roughly 9,000 ft (2,700 m) high, with several peaks as high as Mount Rose (10,778 ft. or 3,285 m), the crest near Yosemite National Park is roughly 13,000 ft (4,000 m) high at Mount Dana and Mount Lyell, and the entire range attains its peak at Mount Whitney. South of Mount Whitney, the range diminishes in elevation, but there are still several highpoints like Florence Peak (12,405 ft. or 3,781 m) and Olancha Peak (12,123 ft. or 3,695 m). The range still climbs almost to 10,000 ft. (3,048 m) near Isabella Lake, but south of the lake, the peaks reach only to a modest 8,000 ft. (2,438 m).

[edit] Geology

See Geology of the Yosemite area for a detailed article about the geology of the central Sierra Nevada.

The geological history of the Sierra Nevada begins in the Jurassic period, approximately 150 million years ago. At that time, an island arc collided with the West coast of North America and raised a set of mountains, in an event called the Nevadan orogeny. This event produced metamorphic rock. At roughly the same time, a subduction zone started to form at the edge of the continent. This means that an oceanic plate started to dive beneath the North American plate. Magma from the melting oceanic plate rose and created plutons of solid granite, deep below the surface. These plutons formed at various times, from 115 million to 87 million years ago. By 65 million years ago, the proto-Sierra Nevada was worn down to a range of rolling low mountains, a few thousand feet high.

About 25 million years ago, the Sierra Nevada started to rise and tilt to the west. Rivers started cutting deep canyons on both sides of the range. The Earth's climate cooled, and ice ages started about 2.5 million years ago. Glaciers carved out characteristic U-shaped canyons throughout the Sierra. The combination of river and glacier erosion exposed the granitic plutons previously buried, leaving only a remnant of metamorphic rock on top of some Sierra peaks. The rocks of the ancient plutons are known as the Sierra Nevada batholith.

Uplift of the Sierra Nevada continues today, especially along its eastern side. This uplift causes large earthquakes, such as the Lone Pine earthquake of 1872.

[edit] Ecology

Main article: Ecology of the Sierra Nevada

The Sierra Nevada are divided into a number of biotic zones^[1]

• The Pinyon pine-Juniper woodland, 5,000-7,000 ft (1,500-2,100 m) east side only
  • Notable species: Pinyon Jay, Desert Bighorn Sheep
• The lower montane forest, 3,000-7,000 ft (1,000-2,100 m) west side, 7,000-8,500 ft (2,100-2,600 m) east side
  • Notable species: Ponderosa pine and Jeffrey pine, California black oak, Incense-cedar, Giant Sequoia, Dark-eyed Junco, Mountain Chickadee, Western gray squirrel, Mule deer, American black bear
• The upper montane forest, 7,000-9,000 ft (2,100-2,700 m) west side, 8,500-10,500 ft (2,600-3,100 m) east side
  • Notable species: Lodgepole pine, Red Fir, Mountain Hemlock, Sierra Juniper, Hermit Thrush, Sage Grouse, Great Grey Owl, Golden-mantled Ground Squirrel, Marten
• The subalpine forest, 9,000-10,500 ft (2,700-3,100 m) west side, 10,500-11,500 ft (3,100-3,500 m) east side
  • Notable species: Whitebark pine and Foxtail pine, Clark's Nutcracker
• The alpine region >10,500 ft (>3,100 m) west side, >11,500 ft (>3,500 m) east side
  • Notable species: Sky Pilot, Pika, Belding's ground squirrel, Yellow-Bellied Marmot, Sierra Nevada Bighorn Sheep

[edit] History

[edit] History of exploration

The earliest identified inhabitants of the Sierra Nevada were the Paiute tribe on the east side and the Mono and Sierra Miwok tribe on the west. Today, passes such as Duck Pass are littered with discarded obsidian arrowheads that date back to trade between tribes. There were also prehistorical territorial disputes between the Paiute and Sierra Miwok tribes^[2] European-American exploration of the mountain range started in the 1840s. In the winter of 1844, Lieutenant John C. Frémont, accompanied by Kit Carson, was the first white man to see Lake Tahoe.

By 1860, even though the California Gold Rush populated the flanks of the Sierra Nevada, most of the Sierra remained unexplored.^[3][4] Therefore, the state legislature authorized the California Geological Survey to officially explore the Sierra (and survey the rest of the state). Josiah Whitney was appointed to head the survey.

Men of the survey, including William H. Brewer, Charles F. Hoffmann, and Clarence King, explored the backcountry of what would become Yosemite National Park in 1863. In 1864, they explored the area around Kings Canyon. King later recounted his adventures over the Kings-Kern divide in his book Mountaineering in the Sierra Nevada. In 1871, King mistakenly thought that Mount Langley was the highest peak in the Sierra and climbed it. However, before he could climb the true highest peak (Mount Whitney), fishermen from Lone Pine, California climbed it and left a note.

Between 1892 and 1897, Theodore Solomons was the first explorer to attempt to map a route along the crest of the Sierra (what would eventually become the John Muir Trail, along a different route). On his 1894 expedition, he took along Leigh Bierce, son of writer Ambrose Bierce.

Other noted early mountaineers included:

• John Muir
• Bolton Coit Brown
• Joseph N. LeConte
• James S. Hutchinson
• Norman Clyde
• Walter Starr, Sr.
• Walter A. Starr, Jr.

Features in the Sierra are named after these men.

[edit] History of the name

In 1542 Juan Rodriguez Cabrillo, sighting the Santa Cruz Mountains while off the peninsula of San Francisco, gave them the name Sierra Nevada meaning "snowy range" in Spanish. As more specific names were given to California's coastal ranges, the name was used in a general way to designate less familiar ranges towards the interior.^[5] In April of 1776 Padre Pedro Font on the second de Anza expedition, looking northeast across the Tulare Valley, described the mountains seen beyond:

Looking northeast we saw an immense plain without any trees, through which the water extends for a long distance, having in it several little islands of lowland. And finally, on the other side of the immense plain, and at a distance of about forty leagues, we saw a great Sierra Nevada whose trend appeared to me to be from south-southeast to north-northwest.^[6]

Its most common nickname is the Range of Light. This nickname comes from John Muir.^[7] This description is due in part to the unusually light colored granite exposed by glacial action.

[edit] Climate and meteorology

Precipitation in the Sierra ranges from 20 to 80 in (500 to 2,030 mm) during fall, winter, and spring. It occurs mostly as snow above 6,000 ft (1,829 m). Rain on snow is common. Summers are dry with low humidity. Temperature averages 42 to 60 degrees Fahrenheit (5.5 to 15.5 degrees Centigrade). The growing season lasts 20 to 230 days, strongly dependent on elevation.^[8]

A unique peculiarity of the Sierra Nevada is that, under certain wind conditions, a large circular tube of air begins to roll on the southeast side. This is known as the "Sierra Nevada Rotor." This "mountain wave" forms when dry continental winds from the east cause the formation of a stacked set of counter-revolving cylinders of air reaching into the stratosphere. As of 2004, no sailplane has found its top. Similar features occur on many mountain ranges, but it is often observed and utilized in the Sierra. The phenomenon was the subject of an Air Force-funded study in the early 1950s called the Sierra Wave Project. All recent world altitude records set in unpowered aircraft were set in the Sierra Nevada Wave, most flown from Mojave Airport.

The Sierra Nevada casts the valleys east of the Sierra in a rain shadow, which makes Death Valley and Owens Valley "the land of little rain".

[edit] See also

• List of Sierra Nevada topics, including lists of mountains, rivers, parks, and other natural features.
• List of guidebooks about the Sierra Nevada
• Ecology of the Sierra Nevada

[edit] References

[edit] External links

• List of Sierra Peaks at climber.org
• The Mountains of California
• Geological Time Line for the Sierra Nevada, National Park Service

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