Yosemite Valley

Yosemite Valley (pronEng|joʊˈsɛməti "yoh-SEM-it-ee") is a world-famous scenic location in the Sierra Nevada mountains of California. It is the centerpiece of Yosemite National Park, attracting visitors from all parts of the globe.

The Valley is the point of entry into the park for the majority of visitors, and a bustling hub of activity during "tourist season", with an array of visitor facilities clustered in the middle. There are both hiking trail loops that stay within the valley and trailheads that lead to higher elevations — all of which afford glimpses of the park's many scenic wonders.

Description

Yosemite Valley is located on the western slope of the Sierra Nevada mountains, 150 miles (240 km) due east of San Francisco. It stretches for 7 miles (11 km) in a roughly east-west direction, with an average width of about 1 mile (1.6 km). More than half a dozen creeks tumble from hanging valleys at the top of granite cliffs that can rise 3000-4000 feet (900-1200 m) above the valley floor, which itself is 4000 ft (1200 m) above sea level. These streams combine into the Merced River, which flows out from the western end of the valley, down the rest of its canyon to the San Joaquin Valley. The flat floor of Yosemite Valley holds both forest and large open meadows, which provide breathtaking views of the surrounding crests and waterfalls.

Below is a short verbal tour of these features, looking first at the walls above, moving west to east as a visitor does when entering the valley, then visiting the waterfalls and other water features, returning east to west with the flow of water.

Granite walls

The first open view from the lower (western) end of the Valley is the great granite monolith El Capitan on the left, and Cathedral Rocks on the right with Bridalveil Fall. Just past this spot the Valley suddenly widens with the Cathedral Spires, then the pointed obelisk of Sentinel Rock to the south. Across the Valley on the northern side are the Three Brothers, rising one above the other like gables built on the same angle -- the highest crest is Eagle Peak, with the two below known as the Middle and Lower Brothers.

To this point, the Valley has been curving gently to the left, to the north. Now a grand curve back to the right begins, with Yosemite Falls on the north, followed by the Royal Arches, topped by North Dome. Opposite to the south is Glacier Point, 3,200 feet (975 m) above the Valley floor. At this point the Valley splits into two, one section slanting northeast, with the other curving from south to southeast. Between them both, at the eastern end of the valley, is Half Dome, the most famous and most recognizable natural feature in the Sierra Nevada. Above and to the northeast of Half Dome is Cloud's Rest; at 9926 feet (3025 m), the highest point around Yosemite Valley.

Water

Snow melting in the Sierra forms creeks and lakes. In the surrounding region, these creeks flow to the edge of the Valley to form cataracts and waterfalls.

A fan of creeks and forks of the Merced River take drainage from the Sierra crest and combine at Merced Lake. The Merced then flows down to the end of its canyon (Little Yosemite Valley), where it begins what is often called the "Giant Staircase". The first drop is Nevada Fall, which drops 594 feet (181 m), bouncing off the granite slope below it. Below is Vernal Fall, 317 feet (97 m) high, one of the most picturesque waterfalls in the Valley. The Merced then descends rapids to meet Illilouette Creek, which drops from the valley rim to form Illilouette Fall. They combine at the base of the gorges that contain each stream, and then flow around the Happy Isles to meet Tenaya Creek at the eastern end of Yosemite Valley proper.

Tenaya Creek flows southwest from Tenaya Lake and down Tenaya Canyon, finally flowing between Half Dome and North Dome before joining the Merced River. The following falls tumble from the Valley rim to join it at various points:

* Yosemite Falls (2,425 ft) Upper Yosemite Fall (1,430 ft), the middle cascades (675 ft), and Lower Yosemite Fall (320 ft). (Yosemite Creek)
* Snow Creek Falls (2,140 ft)
* Sentinel Falls (1,920 ft)
* Ribbon Fall (1,612 ft)
* Royal Arch Cascade (1,250 ft)
* Lehamite Falls (1,180 ft)
* Staircase Falls (1,020 ft)
* Bridalveil Fall (620 ft). (Bridalveil Creek)
* Silver Strand Falls (574 ft)

Natural Yosemite Valley

Geology

"See Geology of the Yosemite area for regional information"

The features in Yosemite Valley are made of granitic rock that was emplaced as plutons miles deep during the late Cretaceous. Over time the Sierra Nevada was uplifted and this rock was exposed at the surface where it was modified by erosion.

The oldest of these granitic rocks occur along the Merced River Gorge west of the valley and are thought to be 114 million years old. The El Capitan pluton intruded the valley forming most of the granitic rock that makes up much of the central part of the valley including Cathedral Rocks, Three Brothers and of course El Capitan. The youngest pluton of Yosemite Valley is the 87 million year old Half Dome granodiorite which makes up most of the rock seen at Glacier Point, the Royal Arches and its namesake Half Dome.

For the last 30 million years, glaciers have periodically filled much of the valley. The most current glaciation, the Wisconsinian was not, however, the most severe. Ice ages previous to the Wisconsinian were colder and lasted longer. Their glaciers were huge and covered nearly all the landmarks around Yosemite Valley except Half Dome, Eagle Peak, Sentinel Dome, and the top of El Capitan. Wisconsinan glaciers, however, only reached Bridalveil Fall in the valley. The glaciers widened the valley, but much of its width is in fact due to previous stream erosion and mass wasting along vertical joints in the valley's walls.

After the retreat of many of these glaciers, a stand of Lake Yosemite developed. The valley floor owes its flatness to sediment deposited by these stands (the last glaciers in the valley were small and did not remove much old lake sediment). The last stand of Lake Yosemite was about 5.5 miles (8.9 km) long and was impounded by a terminal moraine near the base of El Capitan. It was later filled by sediment, becoming a swampy meadow.

The parallel Tenaya Canyon and Little Yosemite Canyon glaciers were, at their largest, 2,000 feet (600 m) deep where they flowed into the Yosemite Valley near the base of Half Dome. They also formed Cloud's Rest behind Half Dome as an arête.

Near Glacier Point there is 2,000 feet (600 m) of mostly glacial sediment with at least six separate sequences of Lake Yosemite sediments. Here, huge and highly erosive pre-Wisconsinan glaciers are thought to be responsible for excavating the bedrock valley floor, and much smaller Wisconsinan glaciers were responsible for depositing glacial debris.

Ecology

The biological community on the floor of Yosemite Valley is a diverse one, with more than 400 species of grasses and wildflowers and thousands of species of insects having been identified there. At the most general level, the Valley can be classified as a dry Yellow pine forest with a number of large open meadows. Plant and animal species that make up a significant part of this natural community include:
* "Trees" - Ponderosa Pine, Lodgepole Pine, Sugar Pine, White Fir, Incense-cedar, California black oak, Interior live oak, Coast Douglas-fir, California laurel, Bigleaf Maple, Scouler's Willow, Pacific Dogwood, White alder, Western Balsam Poplar
* "Shrubs" - Whiteleaf manzanita, Mountain misery, Western azalea, American dogwood, Buckbrush, Deer brush, Sierra gooseberry
* "Wildflowers" - Indian pink, Soap plant, California Poppy, Miner's lettuce, Purple Chinese Houses, Purple milkweed, Star flower, Western buttercup, Pineapple weed
* "Mammals" - California Ground Squirrel, Western Gray Squirrel, Chickaree, Mule Deer, American Black Bear, Bobcat, Coyote
* "Birds" - Dark-eyed Junco, Mountain Chickadee, Black-headed Grosbeak, White-headed Woodpecker, Steller's Jay, American Dipper, Common Raven
* "Reptiles" - Gilbert's Skink, Northern Alligator Lizard, Rattlesnake
* "Amphibians" - Sierra Nevada Salamander

See also: Ecology of the Sierra Nevada

Hiking

Several trails lead out of the Valley, including
* The John Muir Trail --- running 212 miles (341 km) to Mount Whitney
* The Mist Trail --- with views of Vernal Falls and Nevada Fall
* The Four Mile Trail --- leading to Glacier Point.
* The Yosemite Falls Trail --- to the top of Yosemite Falls

History

The recent history of the Valley is the history of human visitors, first Native Americans, then European settlers, then visitors from around the world.

Native Americans in Yosemite

Native Americans have lived in the Yosemite region for as long as 8,000 years. The first people that we have record of was a band of Native Americans that called the Valley "Ah-wah-nee" and themselves the "Ah-wah-nee-chee". This group had trading and family ties to Mono Lake Paiutes from the eastern side of the Sierra Nevada. They annually burned the vegetation on the Valley floor, which promoted the black oak and kept the meadows and forests open. This protected the supply of their principal food, acorns, and reduced the chance of ambush. At the time of first European contact, this band was led by Chief Tenaya (Teneiya), who was raised by his mother among the Mono Lake Paiutes.

The Mariposa Battalion and the first tourists

The first non-natives to see Yosemite Valley were probably members of the 1833 Joseph Walker Party, which was the first to cross the Sierra Nevada from east to west. But the first descriptions of Yosemite came nearly 20 years later. The 1849 California Gold Rush led to conflicts between miners and natives, and the volunteer Mariposa Battalion was formed by the state of California as a punitive expedition against natives in the Yosemite area. In 1851 the Battalion was led by Major James D. Savage, whose trading post on the Merced River had been raided by the Awaneechee. This and other missions resulted in Chief Teneiya and the Awaneechee spending some months on a reservation in the San Joaquin Valley. The band returned the next year to the Valley, but took refuge among the Mono Paiutes after further conflicts with miners. Most of the Awaneechee (along with Teneiya) were chased back to the Valley and killed by the Paiutes after violating hospitality by stealing horses.

While the members of that first expedition of the Mariposa Battalion had heard rumours of what could be found up the Merced River, none was prepared for what they saw March 27, 1851 from what is now called Old Inspiration Point (close to the better visited Tunnel View). Dr. Lafayette Bunnell later wrote:

Camping that night on the Valley floor, the group agreed with the suggestion of Dr. Bunnell to call it "Yo-sem-i-ty", mistakenly believing it to be the native name. (Bunnell was also the first of many to underestimate the height of the Valley walls; one San Francisco newspaper demanded of him that his estimate of 1500 feet (450 m) for the valley rim -- less than half the true height -- be cut in half before publication).

James Hutchings (who organized the first tourist party to the Valley in 1855) along with artist Thomas Ayers, is responsible for much of the earliest publicity about Yosemite, creating articles and entire magazine issues about the Valley. Two of Hutching's first group of tourists, Milton and Houston Mann, built the first toll route into the valley, with development of the first hotels in the area and other trails quickly following. Orchards were planted and livestock grazed in Valley meadows, with damage to native ecosystems as the result.

Yosemite: The first park

Influential figures such as Galen Clark, clergyman Thomas Starr King and leading landscape architect Frederick Law Olmsted were among those who urged Senator John Conness of California to try to preserve Yosemite. President Abraham Lincoln signed a bill on June 30, 1864 granting Yosemite Valley and the Mariposa Grove of Giant Sequoias to the State of California "for public use, resort and recreation," the two tracts "shall be inalienable for all time". This was the first time in history that a federal government had set aside scenic lands simply to protect them and to allow for their enjoyment by all people.

There is a difference between designating an area a park and making it work. California did not set up an administration for the park until 1866 which appointed Galen Clark as the parks guardian. An 11 year struggle followed to resolve homesteading claims in the valley. The challenge of increasing tourism, with the need to first build stagecoach roads, then the Yosemite Valley Railroad, along with hotels and other facilities in and around the Valley was met during the rest of the 19th century. But much environmental damage was caused to the valley itself at that time. The problems that Yosemite Park had under state control was one of the factors in establishing Yellowstone National Park as the first completely national park in 1872.

Due to the difficulty of traveling there, early visitors to the valley came for several weeks to a couple of months and brought their entire family and many of their possessions. Early hotels were therefore set up for extended stays and catered primarily to wealthy patrons who could be away from home for extended periods. A good example of one of these hotels still in operation is the Wawona Hotel which was constructed in the 1880s.

While the Valley was now a park, the surrounding territory was still subject to logging, mining and grazing. John Muir publicized the damage to the subalpine meadows surrounding the Valley, and in 1890, a national park was created which included a much larger territory, enclosing Yosemite Valley and Mariposa Grove. As with Yellowstone, the new federal park was put under U.S. Army jurisdiction until 1914. In 1906 the Valley and Mariposa Grove was ceded back to the federal government. The National Park Service took over Yosemite upon its creation in 1916.

Modern history

Curry Village used to be the site where villagers and visitors watched the famous Yosemite Firefall. These "falls" were really red hot embers that were dropped in large batches from Glacier Point. This practice was stopped in 1969 as part of the Park Service's long process of de-emphasizing artificial park attractions.

On July 6, 1996 a massive rock slide, weighing an estimated 60-80,000 tons, crashed 1800 feet (550 m) into the valley from the east side of Glacier Point, travelling at over 160 mph (260 km/h). Dust blanketed that part of the valley for days, and the wind speed in front of the slide is estimated to have been 300 mph (480 km/h). One person was killed in the slide.

Yosemite is now a world rock climbing attraction. The massive 'big walls' of granite have been climbed countless times since the 1950s and have pushed climbers' abilities to new heights. While climbers traditionally take several days to climb the monoliths, bivvying on the rock faces, modern climbing techniques have allowed ascents to be made in mere hours. Many climbers stay at Camp 4 before beginning their big wall assaults.

Half Dome figures prominently on the reverse side of the California state quarter.

Gallery

See also

* Geology of the Yosemite area
* History of the Yosemite area

References

* "A Natural History of California", Allan A. Schoenherr, UC Press, ISBN 0-520-06922-6
*"Geology of National Parks: Fifth Edition", Ann G. Harris, Esther Tuttle, Sherwood D., Tuttle (Iowa, Kendall/Hunt Publishing; 1997) ISBN 0-7872-5353-7
*"Camp 4: Recollections of a Yosemite Rockclimber", Steve Roper, The Mountaineers, ISBN 0-89886-587-5

External links

* [http://www.yosemite.ca.us/history/geologic_story_of_yosemite/ The Geologic Story of Yosemite Valley by N. King Huber] (USGS, 1987) authoritative and up-to-date summary of Yosemite's geology
* [http://www.ucpress.edu/books/pages/8119/8119.ch04.html Origin of Yosemite Valley, Chapter 4, "Glaciers of California", by Bill Guyton]
* [http://thehive.modbee.com/?q=node/153 Historic Yosemite Indian Chiefs - with photos]
* [http://www.halfdome.net/cams/ahw_movie_01.php Daily updating time-lapse movies of Yosemite Valley]