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:"Yosemite" redirects here. For the Looney Tunes/Merrie Melodies character, see Yosemite Sam. Yosemite National Park (pronounced "Yo-SEM-it-tee", IPA ) is a national park largely in Mariposa County, and Tuolumne County, California, United States. The park covers an area of 1,189 mi² (3,081 km²) and reaches across the western slopes of the Sierra Nevada mountain chain. Yosemite is visited by over 3 million visitors each year, with most only seeing Yosemite Valley. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its spectacular granite cliffs, waterfalls, clear streams, Giant Sequoia groves, and biological diversity (about 89% of the park is designated wilderness area). It was also the first park set aside by the U.S. federal government. Although not the first designated national park, Yosemite was a focal point in the development of the national park idea, largely owing to the work of people like John Muir. Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and it supports a diversity of plants and animals. The park has an elevation range from 2,000 to 13,114 feet (600 to 4000 m) and contains five major vegetation zones: chaparral/oak woodland, lower montane, upper montane, subalpine and alpine. Of California's 7,000 plant species, about 50% occur in the Sierra Nevada and more than 20% within Yosemite. There is suitable habitat or documented records for more than 160 rare plants in the park, with rare local geologic formations and unique soils characterizing the restricted ranges many of these plants occupy. The geology of the Yosemite area is characterized by granitic rocks and remnants of older rock. About 10 million years ago, the Sierra Nevada was uplifted and then tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, narrow canyons. About 1 million years ago, snow and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet (1200 m) during the early glacial episode. The downslope movement of the ice masses cut and sculpted the U-shaped valley that attracts so many visitors to its scenic vistas today.
Geography
Rocks and erosion Almost all of the landforms in the Yosemite area are cut from the granitic rock of the Sierra Nevada Batholith (a batholith is a large mass of intrusive igneous rock that formed deep below the surface). About 5% of the park (mostly in its eastern margin near Mount Dana) are from metamorphosed volcanic and sedimentary rocks. These rocks are called "roof pendants" because they were once the roof of the underlying granitic rock. Erosion acting upon different types of uplift-created joint and fracture systems is responsible for creating the valleys, canyons, domes, and other features we see today (these joints and fracture systems do not move, and are therefore not faults). Spacing between joints and fracture systems is largely due to the amount of silica in the granite and granodiorite rocks; more silica tends to create larger spaces between joints and fractures and thus a more resistant rock. Pillars and columns, such as Washington Column and Lost Arrow, are created by cross joints. Erosion acting on master joints is responsible for creating valleys and later canyons. The single most erosive force over the last few million years has been from large alpine glaciers, which have turned the previously V-shaped river-cut valleys into U-shaped glacial-cut canyons (such as Yosemite Valley and Hetch Hetchy Valley). Exfoliation (caused by the tendency of crystals in plutonic rocks to expand at the surface) acting on granitic rock with widely spaced joints is responsible for creating domes such as Half Dome and North Dome and inset arches like Royal Arches. Popular features Yosemite Valley represents only one percent of the park area, but this is where most visitors arrive and stay. El Capitan, a prominent granite cliff that looms over the valley, is one of the most popular world destinations for rock climbers because of its diverse range of difficulties and numerous established climbing routes in addition to its year-round accessibility. Impressive granite domes such as Sentinel Dome and Half Dome rise 3,000 feet and 4,800 feet (900 and 1450 m), respectively, above the valley floor. The high country of Yosemite contains beautiful areas, such as Tuolumne Meadows, Dana Meadows, the Clark Range, the Cathedral Range, and the Kuna Crest. The Sierra crest and the Pacific Crest Trail run through Yosemite, with peaks of red metamorphic rock, such as Mount Dana and Mount Gibbs, and granite peaks, such as Mount Conness. Mount Lyell is the highest point in the park. The park has three groves of ancient Giant Sequoia (Sequoiadendron giganteum) trees; the Mariposa Grove (200 trees), Tuolumne Grove (25 trees), and the Merced Grove (20 trees). Giant Sequoia are the most massive trees in the world and are one of the tallest and longest-lived (Coast Redwoods that live along the Northern Californian coast are the tallest and the Great Basin Bristlecone Pine of Eastern California are the oldest). These trees were much more widespread before the start of the last Ice Age (Geology of U.S. Parklands, page 227). Waterfalls Yosemite is famous for its high concentration of waterfalls in such a limited area. Although hundreds of ephemeral waterfalls appear in different places during rainfall, the primary waterfalls are as follows, in alphabetical order: Image:Half Dome from North Dome-1200px.jpg|Half Dome from North Dome Image:Sequoiadendron1.jpg|Mariposa Grove Image:Tenaya Lake 2.jpg|Tenaya Lake Image:Mount Dana.jpg|Mount Dana Image:Waterfalls.jpg|Waterfalls from Glacier Point Image:P7080181.JPG|Half Dome from Glacier Point Image:Chilnualna Falls.jpg|Chilnualna Falls Image:Yosemite falls1.jpg|Yosemite Falls Image:Yosemite Vernal Fall10.JPG|Vernal Fall Image:Yosemite Nevada Fall11.JPG|Nevada Fall Image:Yosemite valley1.jpg|Half Dome from Glacier Point Image:Yosemite Valley observation.jpg|Yosemite Valley Water and ice Tuolumne and Merced River systems originate along the crest of the Sierra Nevada in the park and have carved river canyons 3,000 to 4,000 feet (900 to 1200 m) deep. The Tuolumne River drains the entire northern portion of the park, an area of approximately 680 square miles (1760 km²). The Merced River begins in the park's southern peaks, primarily the Cathedral and Clark Ranges, and drains an area of approximately 511 square miles (1320 km²). Hydrologic processes, including glaciation, flooding, and fluvial geomorphic response, have been fundamental in creating landforms in the park. The park also contains approximately 3,200 lakes (greater than 100 square meters), two reservoirs, and 1,700 miles (2700 km) of streams, all of which help form these two large watersheds. Wetlands in Yosemite occur in valley bottoms throughout the park, and are often hydrologically linked to nearby lakes and rivers through seasonal flooding and groundwater movement. Meadow habitats, distributed at elevations from 3,000 to 11,000 feet (900 to 3500 m) in the park, are generally wetlands, as are the riparian habitats found on the banks of Yosemite's numerous streams and rivers. Numerous sheer drops, glacial steps and hanging valleys in the park provide many places for waterfalls to exist, especially during April, May, and June (the snowmelt season). Located in Yosemite Valley, the 2425-foot-high (782 m) Yosemite Falls is the highest in North America and the third highest in the world. Also in the valley is the much lower volume Ribbon Falls, which has the highest single vertical drop, 1612 feet (492 m) (Geology of U.S. Parklands, page 227). Perhaps the most prominent of the Yosemite waterfalls is Bridalveil Fall, which is the waterfall seen from the Tunnel View viewpoint at the east end of the Wawona Tunnel. Wapama Falls in Hetch Hetchy Valley is another notable waterfall. All glaciers in the park are relatively small glaciers that occupy areas that are in almost permanent shade, such as north- and northeast-facing cirques. Lyell Glacier is the largest glacier in the Sierra Nevada (and therefore the park) and covers 160 acres (65 ha). None of the Yosemite glaciers is a remnant of the much, much larger Ice Age alpine glaciers responsible for sculpting the Yosemite landscape. Instead, they were formed during one of the neoglacial episodes that have occurred since the thawing of the Ice Age (such as the Little Ice Age). Global warming has reduced the number and size of glaciers around the world. Many Yosemite glaciers, including Merced Glacier, which was discovered by John Muir in 1871 and bolstered his glacial origins theory of the Yosemite area, have disappeared and most of the others have lost up to 75% of their surface area (Geology of U.S. Parklands, page 228). Climate The area of the park has a Mediterranean climate, meaning almost all yearly precipitation normally falls during mild winter and the other seasons are nearly dry (less than 3% of precipitation falls in the typically long, hot summers). Due to orographic lift precipitation increases with elevation until around 8000 feet (2400 m) when it slowly decreases to the crest. Precipitation amounts vary from 36 inches (915 mm) at 4,000 feet (1200 m) elevation to 50 inches (1200 mm) at 8,600 feet (2600 m). Snow does not typically persist on the ground until November in the high country. It accumulates all winter and into March or early April. Temperature decreases with increasing elevation. Temperature extremes are moderated by the fact that Yosemite is only about 100 miles (160 km) from the Pacific Ocean. An anticyclone sits off the coast of California in the summer, sending cool air masses toward the Sierra Nevada that result in clean dry air in the Yosemite area. Mean daily temperatures range from 25 to 53 °F (-3.9 to 11.5 °C) at Tuolumne Meadows at 8,600 feet (2,600 m). At South Entrance near Wawona (elevation 6192 feet; 1887 m), mean daily temperature ranges from 36 to 67 °F (2.2 to 19.4 °C). At the lower elevations below 5,000 feet (1525 m), temperatures are hotter; the mean daily high temperature at Yosemite Valley (elevation 3,966 feet; 1209 m) varies from 46 to 90 °F (7.8 to 32.2 °C). At elevations above 8,000 feet (2440 m), the hot, dry summer temperatures are moderated by frequent summer thunderstorms, along with snow that can persist into July. The combination of dry vegetation, low relative humidity, and thunderstorms results in frequent lightning-caused fires as well. History Main article: History of the Yosemite area The Ahwahnechee and the Mariposa Wars Paiute and Sierra Miwok peoples lived in the area for decades before the first white explorations into the region. A band of Native Americans called the Ahwahnechee* lived in Yosemite Valley when the first non-indigenous people entered it. The California Gold Rush in the mid-19th century dramatically increased white travel in the area. United States Army Major James Savage led the Mariposa Battalion into Yosemite Valley in 1851 while in pursuit of around 200 Ahwaneechees led by Chief Tenaya as part of the Mariposa Wars. Accounts from this battalion were the first confirmed cases of Caucasians entering the valley. Attached to Savage's unit was Dr. Lafayette Bunnell, the company physician, who later wrote about his awestruck impressions of the valley in The Discovery of the Yosemite. Bunnell is credited with naming the valley from his interviews with Chief Tenaya. Bunnell wrote that Chief Tenaya was the founder of the Pai-Ute Colony of Ah-wah-ne* The Miwoks (and most white settlers) considered the Ahwahnechee to be especially violent due to their frequent territorial disputes, and the Miwok word "yohhe'meti" literally means "they are killers".* Correspondence and articles written by members of the battalion helped to popularize the valley and surrounding area. Tenaya and the rest of the Ahwahneechee were eventually captured and their village burned. They were removed to a reservation near Fresno, California. Some were later allowed to return to the valley but got in trouble after attacking a group of eight miners in 1852. The band fled to take refuge with the nearby Mono tribe, which betrayed its hospitality—each Ahwahneechee was tracked down and killed by the Mono. Early tourists Entrepreneur James Mason Hutchings, artist Thomas Ayres, and two others ventured into the area in 1855, becoming the valley's first tourists. Hutchings wrote articles and books about this and later excursions in the area and Ayres' sketches became the first accurate drawings of many prominent features. Photographer Charles Leander Weed took the first photographs of the Valley's features in 1859. Later photographers included Ansel Adams. Wawona was an Indian encampment in what is now the southwestern part of the park. Settler Galen Clark discovered the Mariposa Grove of Giant Sequoia in Wawona in 1857. Simple lodgings were built, as were roads to the area. In 1879, the Wawona Hotel was built to serve tourists visiting the Grove. As tourism increased, so did the number of trails and hotels. The Yosemite Grant Concerned by the effects of commercial interests, several prominent people, including Galen Clark and Senator John Conness advocated for protection of the area. A park bill passed both houses of the U.S. Congress and was signed by President Abraham Lincoln on June 30, 1864, creating the Yosemite Grant. Yosemite Valley and the Mariposa Grove were ceded to California as a state park and a board of commissioners was proclaimed two years later. The Yosemite Grant counts as a landmark bill, as it predates the establishment of Yellowstone National Park, officially the first "national park". Representations of Giant Sequoia's can be found of Park Service uniforms attesting to the importance of specifically the Mariposa Grove in the development of the National Park idea. Galen Clark was appointed by the commission as the grant's first guardian but neither Clark nor the commissioners had the authority to evict homesteaders (which included Hutchings). The issue was not settled until 1875 when the land holdings were invalidated. Clark and the reigning commissioners were ousted in 1880 and Hutchings became the new park guardian. Access to the park by tourists improved in the early years of the park and conditions in the Valley were made more hospitable. Tourism started to significantly increase after the First Transcontinental Railroad was completed in 1869, but the long horseback ride needed to reach the area was a deterrent. Three stagecoach roads were built in the mid-1870s to provide better access to the growing number of visitors to the Valley. Scottish-born naturalist John Muir first wrote many articles popularizing the area and increasing scientific interest in it. Muir was one of the first to theorize that the major landforms in Yosemite were created by large alpine glaciers, bucking established scientists such as Josiah Whitney, who regarded Muir as an amateur. Muir also wrote scientific papers on the area's biology. Increased protection efforts
Later history The National Park Service was formed in 1916 and Yosemite was transferred to that agency's jurisdiction. Tuolumne Meadows Lodge, Tioga Pass Road, and campgrounds at Tenaya and Merced lakes were also completed in 1916. Automobiles started to enter the park in ever-increasing numbers following the construction of all-weather highways to the park. The Yosemite Museum was founded in the early 1920s through the efforts of Ansel Franklin Hall. To the north of Yosemite Valley but within the park is Hetch Hetchy Valley, which was slated for flooding to create a reservoir and hydroelectric power plant to benefit far-away San Francisco. A nationally polarized fight ensued, pitting preservationists like Muir and his Sierra Club against conservationists like Gifford Pinchot. The U.S. Congress eventually authorized the O'Shaughnessy Dam in 1913 through passage of the Raker Act. Since then, preservationists have convinced Congress to designate 677,600 acres (2,742 km²), or about 89% of the park, as the Yosemite Wilderness — a highly protected wilderness area. The Park Service has also been moving away from allowing touristy inducements to visit the park, such as the famous Firefall (in which red-hot embers were pushed off a cliff near Glacier Point at night). Increasing traffic congestion in Yosemite Valley during the summer months has also been an issue of concern. Proposals to exclude all automobiles in the summer that are not registered at a hotel or campground within the valley have been investigated. This would force all summer day-use visitors in the valley to use the free shuttle system, bike, or walk in the 7-mile-long (11 km) valley. Geology Main article: Geology of the Yosemite area Tectonic and volcanic activity The area of the park was astride a passive continental margin during the Precambrian and early Paleozoic. Sediment was derived from continental sources and was deposited in shallow water. These rocks have since been metamorphosed. Heat generated from the Farallon Plate subducting below the North American Plate led to the creation of an island arc of volcanoes on the west coast of proto-North America between the late Devonian and Permian periods. Later volcanism in the Jurassic intruded and covered these rocks in what may have been magmatic activity associated with the early stages of the creation of the Sierra Nevada Batholith. 95% of these rocks were eventually removed by uplifted-accelerated erosion. The first phase of regional plutonism started 210 million years ago in the late Triassic and continued throughout the Jurassic to about 150 million years before present (bp). Around the same time, the Nevadan orogeny built the Nevadan mountain range (also called the Ancestral Sierra Nevada) to a height of 15,000 feet (4500 m). This was directly part of the creation of the Sierra Nevada Batholith, and the resulting rocks were mostly granitic in composition and emplaced about 6 miles (10 km) below the surface. The second major pluton emplacement phase lasted from about 120 million to 80 million years ago during the Cretaceous. This was part of the Sevier orogeny. Starting 20 million years ago (in the Cenozoic) and lasting until 5 million years ago a now-extinct extension of Cascade Range volcanoes erupted, bringing large amounts of igneous material in the area. These igneous deposits blanketed the region north of the Yosemite region. Volcanic activity persisted past 5 million years BP east of the current park borders in the Mono Lake and Long Valley areas. Uplift and erosion Starting 10 million years ago, vertical movement along the Sierra fault started to uplift the Sierra Nevada. Subsequent tilting of the Sierra block and the resulting accelerated uplift of the Sierra Nevada increased the gradient of western-flowing streams. The streams consequently ran faster and thus cut their valleys more quickly. Additional uplift occurred when major faults developed to the east, especially the creation of Owens Valley from Basin and Range-associated extensional forces. Uplift of the Sierra accelerated again about two million years ago during the Pleistocene. The uplifting and increased erosion exposed granitic rocks in the area to surface pressures, resulting in exfoliation (responsible for the rounded shape of the many domes in the park) and mass wasting following the numerous fracture joint planes (cracks; especially vertical ones) in the now solidified plutons. Pleistocene glaciers further accelerated this process and the larger ones transported the resulting talus and till from valley floors. Numerous vertical joint planes controlled where and how fast erosion took place. Most of these long, linear and very deep cracks trend northeast or northwest and form parallel, often regularly spaced sets. They were created by uplift-associated pressure release and by the unloading of overlying rock via erosion. Sculpting by glaciers A series of glaciations further modified the region starting about 2 to 3 million years ago and ending sometime around 10,000 bp. At least 4 major glaciations have occurred in the Sierra Nevada; locally called the Sherwin (also called the pre-Tahoe), Tahoe, Tenaya, and Tioga. The Sherwin glaciers were the largest, filling Yosemite and other valleys, while later stages produced much smaller glaciers. A Sherwin-age glacier was almost surely responsible for the major excavation and shaping of Yosemite Valley and other canyons in the area. Glacial systems reached depths of up to 4000 feet (1200 m) and left their marks in the Yosemite area. The longest glacier in the Yosemite area ran down the Grand Canyon of the Tuolumne River for 60 miles (95 km), passing well beyond Hetch Hetchy Valley. Merced Glacier flowed out of Yosemite Valley and into the Merced River Gorge. Lee Vining Glacier carved Lee Vining Canyon and emptied into Lake Russel (the much-enlarged ice age version of Mono Lake). Only the highest peaks, such as Mount Dana and Mount Conness, were not covered by glaciers. Retreating glaciers often left recessional moraines that impounded lakes such as Lake Yosemite (a shallow lake that periodically covered much of the floor of Yosemite Valley). Habitats With habitats ranging from thick foothill chaparral to expanses of alpine rock, Yosemite National Park supports over 250 species of vertebrates, which include fish, amphibians, reptiles, birds, and mammals. This high diversity of species is also the result of habitats in Yosemite that are largely intact, compared to areas outside the park where various human activities have resulted in habitat degradation or destruction. Along much of Yosemite's western boundary, habitats are dominated by mixed coniferous forests of Ponderosa Pine, Sugar Pine, Incense-cedar, White Fir, and Douglas Fir, and a few stands of Giant Sequoia, interspersed by areas of Black Oak and Canyon Live Oak. A relatively high diversity of wildlife species are supported by these habitats, due to relatively mild, lower-elevation climate, and the mixture of habitat types and plant species. Wildlife species typically found in these habitats include Black Bear, Bobcat, Gray Fox, Mule Deer, Mountain Kingsnake, Gilbert's Skink, White-headed Woodpecker, Brown Creeper, Spotted Owl, and a wide variety of bat species. In the case of bats, large snags are important as roost sites. Going higher in elevation, the coniferous forests become purer stands of Red Fir, Western White Pine, Jeffrey Pine, Lodgepole Pine, and the occasional Foxtail pine. Fewer wildlife species tend to be found in these habitats, due to their higher elevation, and lower complexity. Species likely to be found include Golden-mantled Ground Squirrel, Chickaree, Marten, Steller's Jay, Hermit Thrush, and Northern Goshawk. Reptiles are not common, but include Rubber Boa, western fence lizard, and Northern Alligator Lizard. As the landscape rises, trees become smaller and more sparse, with stands broken by areas of exposed granite. These include Lodgepole Pine, Whitebark Pine, and Mountain Hemlock that, at highest elevations, give way to vast expanses of granite as treeline is reached. The climate in these habitats is harsh and the growing season is short, but species such as Pika, Yellow-bellied Marmot, White-tailed Jackrabbit, Clark's Nutcracker, and Rosy Finch are adapted to these conditions. Also, the treeless alpine habitats are the areas favored by Sierra Nevada Bighorn Sheep. This species, however, is now found in the Yosemite area only around Tioga Pass, where a small, reintroduced population exists. At a variety of elevations, meadows provide important, productive habitat for wildlife. Animals come to feed on the green grasses and use the flowing and standing water found in many meadows. Predators, in turn, are attracted to these areas. The interface between meadow and forest is also favored by many animal species because of the proximity of open areas for foraging and cover for protection. Species that are highly dependent upon meadow habitat include Great Gray Owl, Willow Flycatcher, Yosemite Toad, and Mountain Beaver. See also: Biology of the Sierra Nevada Management issues
Visiting Valley Camping / Lodging More often than not guests of Yosemite choose to stay inside Yosemite Valley. Yosemite Valley is the most central region of Yosemite and offers a wide range of attactions. The Valley is of closest proximity to these attractions, to other visitors, and supplies. It hosts the most popular trailheads for waterfalls and domes and offers amazing views of the granite mountains. Thus, when choosing where to stay during a given visit to Yosemite a majority of guests choose the Valley as their temportary living destination. All locations inside the valley, except Camp 4, require prior reservations. Campgrounds are cheap and are what you would expect from normal camping situations, while lodging is pricey and more like what you might find at a hotel (running water, housing structures, etc). Campgrounds Lodging Outside the Valley Camping / Lodging Destinations outside the Valley are more remote and geared towards heavy duty camping. The Valley can be very crowded in peak months and camping outside the Valley can serve as a way to separate from the crowds. There exist campgrounds in all directions from the Yosemite Valley floor. Visitors to these campgrounds are not within walking proxmity to the Valley attractions and will need to drive to the Valley. Unlike staying in the Valley where reservations are required, in most cases these campgrounds are all first-come first-served. Year-Round Campgrounds Seasonal Campgrounds - closed oct-may depending on conditions Lodging Activities
Hiking Over 800 miles (1300 km) of trails are available to hikers—anything from the easy stroll, to the grueling hikes up several park mountains, to multiple-day backpack trips. The park is best divided into 5 sections for the day-user—Yosemite Valley, Wawona/Mariposa Grove/ Glacier Point, Tuolumne Meadows, Hetch Hetchy, and Crane Flat/White Wolf. Numerous books describe park trails, and free information is available from the Park Service in Yosemite. There are also many free resources on the Internet that contain hiking recommendations and advice on Yosemite trails. Most park workers strongly encourage guests to experience portions of the park other than Yosemite Valley. Popular Hiking Trails Driving Destinations While some locations in Yosemite require hiking, other locations can be observed via automobile transportation. Whether is is gaining a different view or perspective of Yosemite or finding a location to swim or relax the following are common practices activities in Yosemite. Driving locations also allow guests to observe the night sky in locations other than their campsite or lodge. Climbing Rock climbing is an important part of Yosemite. Camp 4—a walk-in campground in Yosemite Valley—has been said to be one of the most important places in the world to the history of rock climbing. It is now listed on the National Register of Historic Places. Climbers can generally be spotted in the snow-free months on anything from ten-foot-high (3 m) boulders to the 3,300-foot (1 km) face of El Capitan. Classes are offered by numerous groups on rock climbing. Other Summer Activities Other Winter Activities Much of the park closes due to heavy snow in winter. However, Yosemite Valley is open all year long. Miscellaneous See also | |||||||||||||||||||||||||||||||||||||||||||||||||||||
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