Half Dome

Infobox Mountain
Name = Half Dome
Photo = Half Dome at sunset.jpg
Caption = Half Dome from Yosemite Valley
Elevation = convert|8836|ft|m|0|abbr=on
Location = California, USA
Prominence = convert|1360|ft|m|0|abbr=on
Parent peak = Mount Hoffman cite web
url = http://www.peaklist.org/CAmtnatlas/tables/whitney/ritter.html
title = MOUNT RITTER - California Mountain Atlas
work = Peaklist.org
accessdate = 2008-09-22 ]
Range = Sierra Nevada
Coordinates= coord|37|44|45.6|N|119|31|59.4|W|type:mountain_region:US
Topographic
USGS Half Dome
Type = Granite dome
Age = Cretaceous, 93 Myr
First ascent = 1875 by George G. Anderson
Easiest route = cable route

Half Dome is a granite dome in Yosemite National Park, located at the eastern end of Yosemite Valley — possibly Yosemite's most familiar sight. The granite crest rises more than convert|4737|ft|m|0|abbr=on above the valley floor.

Ascents

As late as the 1870s, Half Dome was declared "perfectly inaccessible", [cite book |last=Jones |first=Chris |title=Climbing in North America |publisher=American Alpine Club / Univ of California Press |date=1976 |location=Berkeley, California |pages=26 |id=ISBN 0-520-02976-3] but it may now be ascended in several different ways. Thousands of hikers reach the top each year by following a trail from the valley floor. The trailhead is only convert|2|mi|km|1|abbr=on from Half Dome itself, but the circuitous route is convert|8.5|mi|km|1|abbr=on long. The final ascent is accomplished by following a pair of metal cables raised on posts up the peak's steep but somewhat rounded east face. The cable route was constructed in 1919, but followed close to the route of George Anderson's October, 1875 first ascent made by drilling iron eyebolts into the smooth granite. [cite book |last=Jones |first=Chris |title=Climbing in North America|pages=27]

Alternatively, over a dozen rock climbing routes lead from the valley up Half Dome's vertical northwest face. Other routes ascend the south face and the west shoulder. The first modern technical route was the Regular Northwest Face route - originally climbed in 1957 by Royal Robbins, Mike Sherrick, and Jerry Gallwas. This 5-day ascent was the first Grade VI climb in the United States. [cite book |last=Jones |first=Chris |title=Climbing in North America|pages=207-211]

Geology

Half Dome is nearly as whole as it ever was. The impression from the valley floor that this is a round dome which has lost its northwest half is an illusion. From Glacier Point or from Washburn Point, Half Dome can be seen as a thin ridge of rock oriented northeast-southwest, with its southeast side almost as steep as its northwest side except for the very top. Although the trend of this ridge, as well as that of Tenaya Canyon, is probably controlled by master joints, 80 percent of the northwest "half" of the original dome may well still be there. What probably happened is that frost splitting of the rock at the back of a tiny glacier against Half Dome above Mirror Lake gradually quarried back the steep northwest face. As the base of the cliff was hewn away, ultimately parts of the sheets parallel to the original upper surface of Half Dome were left projecting outward at the crest of the vertical cliff.

In culture

An image of Half Dome, along with John Muir and the California Condor, appears on the California State quarter, released in January 2005.

Half Dome was originally called "Tis-sa-ack," meaning Cleft Rock in the language of the local Native Americans. Tis-sa-ack is also the name of the fourth route on the formation, ascended by Royal Robbins and Don Peterson over eight days in October 1969. Tis-sa-ack is the name of a mother from a native legend. The face seen in Half Dome is supposed to be hers. [cite book|title=The Lore and Lure of Yosemite|last=Wilson|first=Herbert Earl|year=1922|chapter=Legend of Tis-sa-sack|url=http://www.sacred-texts.com/nam/ca/lly/lly28.htm] Tis-sa-ack is the name of a Mono Lake Paiute Indian girl in the Yosemite Native American legend.Fact|date=July 2007

Half Dome is included in many company and organization logos, including that of the environmental group, the Sierra Club and the game studios Sierra Entertainment.

Half Dome is the inspiration behind The North Face corporate logo.

Hiking the Cables Route

The Half Dome Cables Route hike runs from the valley floor to the top of the dome in convert|8.2|mi|km|0|abbr=on (via the Mist Trail), with convert|4800|ft|m|0|abbr=on of elevation gain. The length and difficulty of the trail used to keep it less crowded than other park trails, but on long summer days there can still be a large crowd at the top and on the trail. The hike can be done from the valley floor in a single long day, but many people break it up by camping overnight in Little Yosemite Valley. The trail climbs past Vernal and Nevada Falls, then continues into Little Yosemite Valley, then north to the base of the northeast ridge of Half Dome itself.

The final convert|400|ft|m|0|abbr=on ascent is steeply up the rock between two steel cables used as handholds.cite web|title=Half Dome Day Hike|url=http://www.nps.gov/yose/planyourvisit/halfdome.htm|work=Yosemite National Park|publisher=National Park Service|accessdate=2007-08-12] The cables are fixed with bolts in the rock and raised onto a series of metal poles in late May (the poles do not anchor the cables). The cables are taken down from the poles for the winter in early October, but they are still fixed to the rock surface and can be used. The National Park Service recommends against climbing the route when the cables are down and when the surface of the rock is wet and slippery. The Cable Route is rated class 3, while the same face away from the cables is rated class 5. [cite book|last=Secor|first=R.J.|title=The High Sierra: Peaks, Passes, and Trails|date=1999|edition=2nd edition|publisher=The Mountaineers|pages=391]

The cable route can be crowded. As many as 1,000 hikers per day sometimes climb the dome on a summer weekend.cite news|title=Death of Sunnyvale hiker on Half Dome called unusual|work=San Jose Mercury News|date=2007-06-19|url=http://www.mercurynews.com/ci_6180679?source=most_emailed] Gloves are recommended for the cable climb, as is proper conditioning, plus sufficient water and food. In past years, a pile of gloves left by hikers could be found by those who did not bring their own [cite news | last = Warszawski | first = Marek | coauthors = | title = The haul to Half Dome | work = The Fresno Bee | pages = | publisher = | date = 10/12/2006 | url = http://www.fresnobee.com/374/story/7072.html | accessdate = 2007-05-15 ] , but as of summer 2007 this pile has been removed as litter by park rangers, and a sign suggests hikers not leave gloves. As of summer 2008, the pile of gloves has returned, and no signs advising against leaving gloves are present.

The top of Half Dome is a large, flat area where climbers can relax and enjoy their accomplishment. The summit offers views of the surrounding areas, including Little Yosemite Valley and the Valley Floor. A notable location to one side of Half Dome is the "Diving Board," where Ansel Adams took his photograph, "Monolith, The Face of Half Dome (1926)."

From 1971 through August 2007, there have been nine fatal falls from the cables, three in 2007. On June 16, 2007, Hirofumi Nohara, a native of Japan working in Sunnyvale, California, slipped and plunged convert|300|ft|m to his death. [cite web | url = http://www.nps.gov/yose/parknews/halfdomefall2007.htm | title = NPS: Hiker Dies on Half Dome in Yosemite National Park ] .

Lightning strikes can be a risk while on or near the summit. On July 27, 1985, five hikers were struck by lightning, resulting in two fatalities [cite news | title=Lightning at Yosemite's Half Dome Kills 2 Climbers; 3 Hurt|date=Jul 29, 1985|work=Los Angeles Times ] .

ee also

*El Capitan
*Sentinel Dome

References

External links

* [http://www.nps.gov/yose/planyourvisit/halfdome.htm Half Dome hike on the NPS website]
* [http://www.yosemite.ca.us/history/geologic_story_of_yosemite/ Geologic Story of Yosemite National Park] by N. King Huber, USGS (adapted PD source)
* [http://www.tierrawiki.org/wiki/index.php?title=Half_Dome Half Dome on TierraWiki.org]
* [http://www.summitpost.org/show/mountain_link.pl/mountain_id/221 Half Dome on Summitpost.org]
* [http://www.outdoordb.org/index.php?title=Half_Dome Hiking Half Dome on OutdoorDB.org]
* [http://www.halfdome.net Daily updating time-lapse movies of Half Dome]
* [http://www.xrez.com/gallery/yosemite/xRez_yose.html xRez Yosemite Gallery] gigapixel images of Yosemite and Half Dome.