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Mount Hood, called Wy'east by the Multnomah tribe, is a stratovolcano in the Cascade Volcanic Arc of northern Oregonmarker. It was formed by a subduction zone and rests in the Pacific Northwest region of the United Statesmarker. It is located about 50 miles (80 km) east-southeast of Portlandmarker, on the border between Clackamasmarker and Hood Rivermarker counties.

The exact height assigned to Mount Hood's snow-covered peak has varied wildly over its history. Modern sources point to three different heights: based on the 1991 U.S. National Geodetic Survey based on a 1993 scientific expedition and of slightly older origin. The peak is home to twelve glaciers. It is the highest mountain in Oregon and the fourth-highest in the Cascade Range.Mount Hood is considered the Oregon volcano most likely to erupt,though based on its history, an explosive eruption is unlikely. Still, the odds of an eruption in the next 30 years are estimated at between 3 and 7 percent,so the USGS characterizes it as "potentially active", but the mountain is informally considered dormant.

Facilities

Timberline Lodgemarker is a National Historic Landmark located on the southern flank of Mount Hood just below Palmer Glaciermarker.

The mountain has six ski areas: Timberlinemarker, Mount Hood Meadowsmarker, Ski Bowlmarker, Cooper Spurmarker, Snow Bunnymarker and Summitmarker. They total over of skiable terrain; Timberline offers the only year-round lift-served skiing in North America.

Mount Hood is part of the Mount Hood National Forestmarker, which has 1.067 million acres (1667 sq mi/4318 km²), four designated wilderness areasmarker which total acres and more than of hiking trails.

Eruption history



The glacially eroded summit area consists of several andesitic or dacitic lava domes; Pleistocene collapses produced avalanches and lahars (rapidly moving mudflows) that traveled across the Columbia River to the north. The eroded volcano has had at least four major eruptive periods during the past 15,000 years.

The last three at Mount Hood occurred within the past 1,800 years from vents high on the southwest flank and produced deposits that were distributed primarily to the south and west along the Sandy and Zigzagmarker Rivers. The last eruptive period took place around 170 to 220 years ago, when dacitic lava domes, pyroclastic flows and mudflows were produced without major explosive eruptions. The prominent Crater Rock just below the summit is hypothesized to be the remains of one of these now-eroded domes. This period includes the last major eruption of 1781–82 with a slightly more recent episode ending shortly before the arrival of Lewis and Clark in 1805. The latest minor eruptive event occurred in August 1907.

The glaciers on the mountain's upper slopes may be a source of potentially dangerous lahars when the mountain next erupts. There are vents near the summit that are known for emitting noxious gases such as carbon dioxide and sulfur dioxide. Prior to the 1980 eruption of Mount St. Helensmarker, the only known fatality related to volcanic activity in the Cascades occurred in 1934 when a climber suffocated in oxygen-poor air while exploring ice caves melted by fumaroles in Coalman Glaciermarker.

Since 1950, there have been several earthquake swarms each year at Mount Hood, most notably in July 1980 and June 2002.

Seismic activity is monitored by the USGS Cascades Volcano Observatory located in Vancouver, Washingtonmarker, which issues daily updates.

The most recent evidence of volcanic activity at Mount Hood consists of fumaroles near Crater Rock and hot springs on the flanks of the volcano.

Elevation

Date Elevation By
1854 Thomas J. Dryer
1854 Belden
1857 Mitchell's School Atlas
1866 Rev. Atkinson
1867 Col. Williamson
1916 Adm. Colbert
1939 Adm. Colbert
1980 USGS using NGVD 29
2008 Encyclopædia Britannica
? NGS using NAVD 88


Since first seen by European explorers in 1792, Mount Hood is believed to have maintained a consistent summit elevation, varying by no more than a few feet due to mild seismic activity. Elevation changes since the 1950s are predominantly due to improved survey methods and model refinements of the shape of the Earth (see vertical reference datum). Despite the physical consistency, the estimated elevation of Mount Hood has varied substantially over the years.

Early explorers on the Columbia River estimated the elevation to be . Two persons in Thomas J. Dryer's 1854 expedition calculated the elevation to be and that the tree line was at about . Two months later, a Mr. Belden claimed to have climbed the mountain during a hunting trip and determined it to be upon which "pores oozed blood, eyes bled, and blood rushed from their ears." Sometime by 1866, Reverend G. H. Atkinson determined it to be . A Portland engineer used surveying methods from a Portland baseline and calculated a height of between . Many maps distributed in the late 1800s cited , though Mitchell's School Atlas gave as the correct value. For some time, many references assumed Mount Hood to be the highest point in North America.

Modern height surveys also vary but not by the huge margins seen in the past. A 1993 survey by a scientific party who arrived at the peaks summit carrying 16 pounds of electronic equipment reported a height of 11,240 feet (3425.952 m), claimed to be accurate to within 1.25 inches. Many modern sources likewise list 11,240 feet as the height. However, numerous others place the peak's height one foot lower, at 11,239 feet. Finally, a height of 11,249 feet has also been reported.

Mount Hood's treeline varies from about , mostly on the western faces, to about , mostly on the eastern side.

Glaciers

Mount Hood glaciers


Mount Hood is host to twelvenamed glaciers or snow fields, the most visited of which is Palmer Glacier, partially within the Timberline Lodge ski areamarker and on the most popular climbing route. The glaciers are almost exclusively above the level, which also is about the average tree line elevation on Mount Hood. More than 80% of the glacial surface area is above .

The glacial surface area totals about 145 million square feet (5.2 square miles) and contains a volume of about 12.3 billion cubic feet (0.084 cubic miles). Eliot Glacier is the largest by volume at , and has the thickest depth measured by ice radar at . The largest surface area is the Coe-Ladd Glacier system at .

Glaciers and snowfields cover about 80 percent of the mountain above the level. The glaciers have lost an average of 34% over the twentieth century (1907-2004). Glaciers on Mount Hood retreated through the first half of the 1900s, advanced or at least slowed their retreat in the 1960s and 1970s, and have since returned to a pattern of retreat. The neo-glacial maximum extents formed in the early 1700s.

During the last major glacial event between 10,000 and 29,000 years ago, glaciers reached down to the to level: a distance of from the summit. The retreat released considerable outwash, some of which filled and flattened the upper Hood River Valley near Parkdalemarker and also formed Dee Flat.

Older glaciation produced moraines near Brightwoodmarker and distinctive cuts on the southeast side; they may date to 140,000 years ago.

Glacier name Area

millions of ft²
Volume

billions of ft³
notes GNIS location
Palmermarker 1.4 0.07 headwaters of the Salmon River
Coalmanmarker (or "Coleman") 0.9 0.04 located between Crater Rock and the summit
White Rivermarker 5.8 0.3 feeds the White River
Newton Clark 21.4 1.4 source of the East Fork Hood River
Eliot 18.1 3.2 source of Tilly Jane Creek and Eliot Branch, tributaries of

Middle Fork Hood River; named for Thomas Lamb Eliot‎
Langille 4.3 0.3 in Hood River watershed
Coe 13.4 1.9 source of Coe Branch, a tributary of Middle Fork Hood River
Ladd 9.7 0.9 source of McGee Creek, a tributary of West Fork Hood River
Glisan
Sandymarker 12.8 0.08 feeds Muddy Fork, a tributary of the Sandy River
Reidmarker 8.1 0.6 feeds the Sandy River
Zigzagmarker 8.3 0.6 feeds the Zigzag Rivermarker
(total) 145.1 12.3


Name



The Multnomah name for Mount Hood is Wy'east. In one version of the legend the two sons of the Great Spirit Sahale fell in love with the beautiful maiden Loowit who could not decide which to choose. The two braves, Wy'east and Klickitat, burned forests and villages in their battle over her. Sahale became enraged and smote the three lovers. Seeing what he had done he erected three mountain peaks to mark where each fell. He made beautiful Mount St. Helensmarker for Loowit, proud and erect Mount Hood for Wy'east, and the somber Mount Adamsmarker for the mourning Klickitat.

There are other versions of the legend. In another telling Wy'east (Hood) battles Pahto (Adams) for the fair La-wa-la-clough (St. Helens). Or againWy'east, the chief of the Multnomah tribe, competed with the chief of the Klickitat tribe. Their great anger led to their transformation into volcanoes. Their battle is said to have destroyed the Bridge of the Gods and thus created the great Cascades Rapidsmarker of the Columbia River.

The mountain was given its present name on October 29, 1792 by Lt. William Broughton, a member of Captain George Vancouver's discovery expedition. Lt. Broughton observed its peak while at Belle Vue Point of what is now called Sauvie Islandmarker during his travels up the Columbia River, writing "A very high, snowy mountain now appeared rising beautifully conspicuous in the midst of an extensive tract of low or moderately elevated land (location of today's Vancouver, Washingtonmarker) lying S 67 E., and seemed to announce a termination to the river." Lt. Broughton named the mountain after a Britishmarker admiral, Samuel Hood.

Early summer panorama of aerial photos of the mountain's crater.


Lewis and Clark were the first Americans to see the mountain, on October 18, 1805. A few days later at what would become The Dallesmarker, Clark wrote "The pinnacle of the round topped mountain, which we saw a short distance below the banks of the river, is South 43-degrees West of us and about . It is at this time topped with snow. We called this the Falls Mountain, or Timm Mountain." Timm was the native name for Celilo Fallsmarker. Clark later noted that it was also Vancouver's Mount Hood.

Two French explorers from Hudson's Bay Company may have traveled into the Dog Rivermarker area east of Mount Hood in 1818. They reported climbing to a glacier on "Montagne de Neige" (Mountain of Snow), probably Eliot Glacier.

Climbing

Landmarks along the south side climbing route of Mount Hood


Mount Hood seen from Portland


Mount Hood is Oregon's highest point and a prominent landmark visible up to a hundred miles away. It has convenient access and minimum of technical climbing challenges. About 10,000 people attempt to climb Mount Hood each year.

The most popular route, dubbed the south route, begins at Timberline Lodge and proceeds up Palmer glacier to Crater Rock, the large prominence at the head of the glacier. Climbers then proceed around Crater Rock and cross Coalman glacier on the Hogsback, a ridge spanning from Crater Rock to the approach to the summit. The Hogsback terminates at a bergschrund where Coalman glacier separates from the summit rock headwall, and then to the Pearly Gates, a gap in the summit rock formation. Once through the Pearly Gates, climbers proceed to the right onto the summit plateau and then to the summit proper.

Technical ice axes, fall protection, and experience are now recommended in order to attempt the left chute variation or Pearly Gates ice chute. The Forest Service is recommending several other route options due to these changes in conditions (e.g. "Old Chute", West Crater Rim, etc).

Climbing accidents



More than 130 people have died in climbing-related accidents since records have been kept on Mount Hood, the first in 1896.Incidents in April 1986 and December 2006 attracted intense national and international media interest.Though avalanches are a common hazard on other glaciated mountains, most Mount Hood climbing deaths are the result of falls and hypothermia.Despite a quadrupling of forest visitors since 1990, fewer than 50 people require rescue per year.Only 3.4 percent of search and rescue missions in 2006 were for mountain climbers.

Hiking

The Timberline Trail, which circumnavigates the entire mountain, was built in the 1930s by the Civilian Conservation Corps. Typically, the hike is snow-free from late July until the autumn snows begin. A portion of the Pacific Crest Trail is coincident with the Timberline Trail on the west side of Mount Hood.

Ship names



There have been two US Navy ammunition ships named for the mountain. USS Mount Hood was commissioned in July 1944 and was destroyed in November 1944 while at anchor in Manus Naval Base, Admiralty Islandsmarker. Her explosive cargo ignited resulting in 45 confirmed dead, 327 missing and 371 injured.A second ammunition ship, AE-29, was commissioned in May 1971 and decommissioned in August 1999.

See also



References

  1. Most likely to erupt based on history, see
  2. Jackson, K.A. and Fountain, A.G. 2007. Spatial and morphologic change on Eliot Glacier, Mount Hood, Oregon, USA. Annals of Glaciology, 46, 222-226.
  3. Grauer, p. 9


External links




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