Sierra Nevada (U.S.)
Seen Mt Whitney from Whitney Portal from
The Sierra Nevada (Spanish for " snowy mountain range " ) is a mountain range in the western United States, primarily in the U.S. state of California. The highest mountain in the Sierra Nevada, the 4421 meter high Mount Whitney, the highest peak in the continental part of the United States, outside of Alaska.
- 4.1 Western levels of vegetation
- 4.2 East of vegetation
- 4.3 Fauna
- 6.1 Protected Areas
The Sierra Nevada is one of the three mountain ranges that extend to the Pacific coast in the western U.S. from north to south parallel. The 650 km long mountain range extends from Fredonyer Pass in the north to the Tehachapi Mountains in the south. The mountain is located mainly in the area of the U.S. state of California, only a small part of the Carson Range to the east of Lake Tahoe, located on the territory of the State of Nevada.
The mountain range forms the southern continuation of the Cascade Range and is one of the North American Cordillera. Among the eastbound Rocky Mountains, the Sierra Nevada is separated by the Great Basin between the Sierra Nevada and the California Coast Ranges extends only about 30 m lying to a large extent on the sea California Central Valley.
In contrast to the Cascade Range, which is divided into several mountain ranges and has striking volcanic peaks, the Sierra Nevada mountain range forms a single. With a length of 640 km and a width of 80 to 130 km, it is considered to be the longest and highest mountain range in the U.S.. From the west, the mountain rises gently, while in the east along California 's eastern border with one of the steepest rock barrier in the world, it falls to the Great Basin.
In the north, the Sierra Nevada is about 2700 m high, the middle part reaches a height of almost 4000 meters and its highest point is Mount Whitney in the southern part. The alpine zone above 2500 m is called the High Sierra and extends as over 300 km long and 30 km wide strip from Pyramid Peak at Lake Tahoe to Cottonwood Pass. To the Mount Whitney are 12 other peaks with a height of over 4200 m, of which some three km steeply rising high above the Great Basin to the east. To the south of Mount Whitney Mountain is rapidly flatter and only reached at the Lake Isabella a height of 3000 m.
- Mount Whitney, 4421 m
- Mount Williamson, 4390 m
- North Palisade, 4341 m
- Mount Muir, 4272 m
- Mount Humphreys, 4265 m
- Mount Keith, 4262 m
- Red Slate Mountain, 4013 m
- Mount Ritter, 4010 m
- Mount Lyell, 3999 m
- Cathedral Peak, 3326 m
- Half Dome, 2693 m
- El Capitan, 2,307 m
Until about 130 million years ago the area of today's Sierra Nevada was covered by sea. The formation of the Sierra Nevada began in the Triassic. During this time, collided as a result of continental drift, an island arc with the western American coast and put a mountain formation in transition, where metamorphic rocks were formed, which today form the essential part of the Sierra Nevada. Due to the collision of the Pacific to the North American plate during the Mesozoic Era, about 250 million years ago molten rock masses penetrated far into the upper, consisting of marine sediments layers and solidified as Batholithe to granite. Before about 80 million years ago the batholith began to unfold itself. The deposited on the granite rocks, marine sediments were thereby partially removed, and pitched in valleys from. The gold contained in the sediments formed the basis for the 1849er Gold Rush. The lifting of the batholith was strongest in the east. The large gash on the eastern edge of the Sierra Nevada is one of the most impressive geological phenomena of the world, a three mile-high wall that has arisen in a block especially by raising the earth's crust along a trench. In its present form the Sierra Nevada is a young mountain range, in about 25 to 2 million years ago, there was lifted up in the Tertiary.
Its present form was the mountain range by weathering and erosion. Westward flowing rivers ate deep valleys into the rock. During the Pleistocene there were at least three glaciations in the Sierra Nevada, between which lay a long warm periods. In contrast to the glaciation that covered much of North America, the glaciation of the Sierra Nevada was mixed. Some areas were not, in the northern part only the higher peaks were glaciated. The area south of Donner Pass to the upper Kern River was covered by numerous, to the east and west extending glaciers. The glaciers tore rocks from the mountain flanks, forming the V-shaped river valleys into U-shaped trough valleys. Streams that poured down during the glaciation on ice, fall after the retreat of the glaciers as waterfalls into the valley. In this way, the Yosemite Valley and the river valleys of the San Joaquin were molded Kings, Kaweah and Kern River. When the last ice age ended about 10,000 years ago, the glaciers had melted and left behind moraines and thousands of mountain lakes. The largest lakes in the area of the Sierra Nevada are Lake Tahoe and Mono Lake. The approximately 60 glaciers, which cover the summit of Mount Lyell, the Palisades and other mountains of the High Sierra, are no remains of Ice Age glaciers, but up to two kilometers long hanging glacier that originated during a cooler period about 4000 years ago.
The Sierra Nevada acts as a huge weather divide, which decreases the coming of the Pacific easterly winds almost all the moisture. The climate of the mountain range itself varies from hot desert climate at the eastern foot of the mountains up to arctic-alpine climate at the peaks.
Due to the high pressure areas off the coast of the western side of the mountain range to 2100 m height from a maritime climate, with cool to warm summers and warm, wet winters is determined. The maritime influence decreases with increasing distance to the ocean. Most precipitation falls from October to April, in the summer the mountain ridge is frequently hit by thunderstorms. The precipitation ranges from less than 250 mm annually on the South Fork of the Kern River to over 2000 mm in the mountains to the North Fork of the Feather River. The amount of rainfall decreases from north to south. Although the main ridge to the south is more than twice as high as in the north, the rainfall in the south is only half the amount in the north of the mountain range. On the west side falls in the higher elevations from 1500 m the most precipitation as snow, in the lower layers as rain. In the deepest layers, at the foothills of the Central Valley California, snow is extremely rare and can not fall for decades. With increasing height also increases the amount and frequency. In the highest elevations of precipitation is somewhat reduced, because they are above the maximum height of coming from the Pacific humid air masses. The Sierra Nevada is a world with one of the regions with the highest snowfall. On January 4, 1982 there was at Echo Summit 1.7 m of fresh snow, the second highest amount ever recorded in the United States. 1982 there was a snow storm on Donner Pass 4.7 meters of snow, also the second highest ever recorded in the United States height. In January 1991, fell at Tamarack within one month of 9.90 m, in the winter of 1906 /07 over 22 m of fresh snow.
The summer temperature means moving from 5.5 to 15.5 ° C. Boreales climate with average values in the coldest month below -2 ° C and heavy snow dominates the highlands of the Sierra Nevada. Fall to the tree line at 3000 m the spring, summer and autumn in the period from mid-July to mid-September, although there may be frost every night at this altitude.
The regions on the east side, which are separated by the mountain chain of the ocean, experience a more continental climate with warm summers, cold winters, large daily and seasonal temperature fluctuations and lower humidity. In winter, the precipitation falls from an altitude of 1200 m mostly as snow, but only in small amounts.
The Sierra Nevada is the main water supplier in California. The winter snow is the source for the water supply of the California longitudinal valley and the Owen Valley's and thus for about 3/4 of California's population and almost all agriculture. The winter of 2013/14 had brought to the middle of January 2014, only 7 % of the usual rainfall in the Sierra, so that Governor Jerry Brown declared a state of emergency water. For agriculture, conversion to water-saving crops is expected, which will lead to supply problems and price increases.
Flora & Fauna
For the Sierra Nevada at least 1,300 species of vascular plants are known, along with numerous mosses and lichens. Furthermore, there are at least 450 vertebrate species.
Western levels of vegetation
The precipitation -rich west side of the Sierra Nevada can be divided into several successive stages of vegetation:
- The foothills range from about 60 to about 1000 m, where they merge in mountain forests. In the hilly and crisscrossed by gullies fall area has a Mediterranean climate with warm dry summers and cool, rainy winters. The present vegetation consists of grasslands, among other things, brome, wild oats and alfalfa. The original prairie vegetation, among other things, Rispengräsern, was destroyed in the 19th century by burning and intensive grazing by cattle and sheep, and is only in residues obtained as in the 634 -hectare sanctuary of the Jepson Prairie or restored. The higher, north-facing and thus more humid mountain slopes are often covered with forests of California white pine, plus blue oak and California white oaks. The sunnier and therefore drier slopes are covered with chaparral. Blue Oak
- From about 750 to 1000 m start the mountain forests of the lower layers, which extend to a height of about 1800 m. This zone is dominated by temperate summers and mild winters, the dominant tree of this zone is the yellow pine, which can be reached in favorable locations diameter of up to 2.50 m and heights of over 60 m. Other frequently occurring trees in the dense forests of the California black oak, incense cedar, sugar pine and fir Colorado. The forest area is characterized by deep canyons, which also Douglas fir, California bay, Quercus chrysolepis and the California Nutmeg grow.
- The forests of the western slopes of the Sierra Nevada are the world's only natural location of the giant sequoia tree, which grows in trees at altitudes 1350-2500 m. On an approximately 420 km long and 20 km wide strip on the western slope of the Sierra Nevada there are still about 70 of these giant sequoia groves. General Sherman Tree, a giant sequoia in Sequoia National Park
- From a height of 1800 m, the forest turns into a forest of pines and superb coastal pines. In the northern Sierra Nevada peaks are often covered with a herd of magnificent fir trees that grow to a height of 2700 meters. The dense splendor - fir forests are much shadier and thus cooler than their surroundings and thus cause a different microclimate. Rare grow in these forests still coastal pine and western Weymouth pines. The understory consists of purse flowers ( Ceanothus ), Chrysolepis and bearberry.
- In the subalpine zone above 2700 m to the tree line still growing mountain hemlock, fir superb, coastal pine and western Weymouth pines. On the granite also adapted the American West juniper. At the southern slopes height stocky white pine grows even up to 3300 m.
- In the rocky desert of the alpine zone above 3000 m only a few alpine plants grow. Up to an altitude of 3650 m, the white -stemmed pine reaches a height of 50 cm. On the east side grow stunted specimens of mountain hemlock and coastal pines up to about 3400 m. In isolated locations near the tree line grows in the southern Sierra Nevada, the foxtail pine.
Eastern vegetation stages
The lying in the rain shadow of the eastern slopes of the Sierra Nevada are excreted in the desert of the Great Basin. The upper levels of vegetation in the east of the Sierra Nevada are similar to those of the west side, however, are shifted to higher altitudes are able and by the steep demolition of the east side of the Sierra Nevada is much more compact and less pronounced. From the alpine zone up to the semi-desert lying in places only a little more than three kilometers in a straight line.
- At the tree line still grows a mountain forest of coastal pines and white -stemmed pines. The mountain forests of the lower altitudes consists of the curved pine and fir trees Berghemlock, in drier locations eventually from Jeffrey pines and firs splendor. Along the streams grows the American Aspen Tree, grows in drier locations Sagebrush up to an altitude of 3000 m. The foothills of the Sierra Nevada to the east are dominated by the single-blade jaw, plus Utah Juniper and Pinus edulis before the coniferous forest over time into the dry vegetation of the Great Basin.
The dense mountain forests of the Sierra Nevada are habitat for numerous small mammals such as chipmunks, Golden-mantled ground squirrel, Sierra - pocket gophers, squirrels and stubby tail Ursons. Your hunters are ermine, long swan Zwiesel, pine martens and, much rarer fish marten. Larger mammals include mule deer, cougars, bobcats, and black bears. In the alpine zone bighorn sheep, pikas, Belding 's Ground Squirrel and Yellow-bellied marmots are found. Among the many bird species include Bartkauze, Great Horned Owl, Clark's Nutcracker, rocky mountain mountain chickens and quails. In the lakes, rivers and streams Ptychocheilus grandis, Mylopharodon Conocephalus, white fish, Cottus gulosus, Catostomus occidentalis, and rainbow trout live.
It was named by the Spanish Sierra Nevada de Anza expedition, which explored California in 1776. The Franciscan monk Pedro Font saw during the expedition of a hill near the Bay of San Francisco behind a vast, treeless plain a powerful, schneebedecktge mountain range that runs from south - southeast to north-northwest. In his diary and on a sketch map, he noted the name " Sierra Nevada ".
As the first white man who crossed the Sierra Nevada, Jedediah Smith applies, which they crossed together with two companions in May 1827 by west to east over the Ebbetts Pass. Between 1843 and 1844 John Charles Frémont explored essential parts of the mountains. Through the California gold rush, thousands of gold seekers arrived in the Sierra Nevada. The California Trail across the 2162 m high Donner Pass was used in the 19th century by thousands of gold-seekers and immigrants.
The prospectors deforested or burned numerous forests off to look for gold and to gain timber. The deforested or burned areas were used in the subsequent period as pasture for huge sheep and cattle. At the same time was operated in much of the Sierra Nevada intensive timber industry until 1890 several laws use by agriculture and forestry regulated or the areas were placed under nature protection. To the most important conservation activists for the Sierra Nevada was from Scotland native John Muir, who from 1868 until his death in 1914 explored the mountains and it made world famous with his descriptions. From scientists Muir became a pioneer of nature conservation, in 1892 the Sierra Club founded and successfully started for the creation of national parks. First Schutzgiebet 1864 Mariposa Grove was established, which rose in 1906, founded in 1890, Yosemite National Park. In the 1890s, the establishment of Sequoia and General Grant Grove National Parks was made. The General Grant Grove went 1940 in Kings Canyon National Park.
Environment and Conservation
Among the current threats to the mountains of the Sierra Nevada is one of the air pollution in California, particularly in the San Joaquin Valley, which leads to the death of young pines and giant sequoias. The rivers that flowed westward from the Sierra Nevada in California's Central Valley, caused during the snowmelt often severe flooding. Many rivers have been dammed for flood protection and are now used for irrigation, water supply for industry and households in the summer months. As a result, less and less water flows directly over the rivers into the sea, but it is used at least once before it is discharged into the sea or into the groundwater.
In the area of the Sierra Nevada are the Yosemite, Kings Canyon and Sequoia National Park, three National Parks, with the Devil's Postpile, a National Monument, nine national forests, and numerous state parks. The high mountains of the southern Sierra Nevada is protected by 20 contiguous Wilderness Area as the Ansel Adams Wilderness and the John Muir Wilderness.
The National Parks, especially Yosemite National Park, are heavily visited during the summer excursions. The John Muir Trail as a long-distance trail through the mountains. The best known of the many because of abundance of snow ski areas of the Sierra Nevada 's Squaw Valley.