Mount Hood

Mount Hood's snow-covered peak rises 11,249 feet (3,429 m)^[1] and is home to twelve glaciers.^[6] (Older surveys said 11,239 feet, which is still often cited as its height). It is the highest mountain in Oregon and the fourth-highest in the Cascade Range.^[7] Mount Hood is considered the Oregon volcano most likely to erupt,^[8] 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,^[9] so the USGS characterizes it as "potentially active", but the mountain is informally considered dormant.^[9]

Facilities

Mount Hood is part of the Mount Hood National Forest, which has 1.067 million acres (1667 sq mi/4318 km²), four designated wilderness areas which total 189,200 acres (295.6 sq mi/766 km²) acres and more than 1,200 miles (1,900 km) of hiking trails.^[12]

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 Zigzag 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.^[13]

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. Helens, 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 Glacier.

Glaciers

Mount Hood is host to twelve^[17]^[18] named glaciers or snow fields, the most visited of which is Palmer Glacier, partially within the Timberline Lodge ski area and along the most popular climbing route. The glaciers are almost exclusively above the 6,000-foot (1,800 m) level, which also is about the level of the average tree line on Mount Hood. More than 80% of the glacial surface area is above 7,000 feet (2,100 m).^[19]

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 3.2 billion cubic feet (91,000,000 m³), and has the thickest depth measured by ice radar at 361 feet (110 m). The largest surface area is the Coe-Ladd Glacier system at 23,100,000 square feet (2,150,000 m²).

Name

The Multnomah name for Mount Hood is Wy'east. Legend says the name Wy'east comes from a chief of the Multnomah tribe, the tribe after which Multnomah County was named. The chief competed for the attention of a woman who was also loved by the chief of the Klickitat tribe. The anger that the competition generated led to their transformations into volcanoes, with the Klickitat chief becoming nearby Mount Adams and the target of their affection becoming Mount St. Helens. Their battle was said to have destroyed the Bridge of the Gods and thus created the Great Cascades of the Columbia River.^[21]

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 Island 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, Washington) lying S 67 E., and seemed to announce a termination to the river." Lt. Broughton named the mountain after a British admiral, Samuel Hood.^[7]

Lewis and Clark were the first Americans to see the mountain on October 18, 1805. A few days later at what would become The Dalles, 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 37 miles. It is at this time topped with snow. We called this the Falls Mountain, or Timm Mountain." Timm was the native name for Celilo Falls. Clark later noted that it was also Vancouver's Mount Hood.^[22]^[23]

Two French explorers from Hudson's Bay Company may have traveled into the Dog River area east of Mount Hood in 1818. They reported climbing to a glacier on "Montagne de Neige" (Mountain of Snow), probably Eliot Glacier.^[22]

Climbing

Its status as Oregon's highest point, a prominent landmark visible up to a hundred miles away, convenient access, and relative lack of technical climbing challenges lure many to climb Mount Hood. About 10,000 people attempt to climb each year.^[24]

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.^[25]

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 change in conditions ("Old Chute," West Crater Rim, etc).^[26]

Climbing accidents

More than 130 people have died in climbing-related accidents since records have been kept on Mount Hood, the first in 1896.^[27] Incidents in April 1986 and December 2006 attracted intense national and international media interest. Though avalanches are popularly considered a hazard, most climbing deaths are the result of falls and hypothermia.^[28] Despite a quadrupling of forest visitors since 1990, fewer than 50 people require rescue per year.^[29] Only 3.4 percent of search and rescue missions in 2006 were for mountain climbers.^[30]

Hiking

The Timberline Trail, which circumnavigates the entire mountain, was built in the 1930s by the Civilian Conservation Corps. Typically, the 40.7-mile (65.5 km) 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.^[31]

Ship names

There have been two US Navy ammunition ships named for the mountain. USS Mount Hood (AE-11) was commissioned in July 1944 and was destroyed in November 1944 while at anchor in Manus Naval Base, Admiralty Islands. Her explosive cargo ignited resulting in 45 confirmed dead, 327 missing and 371 injured.^[32] A second ammunition ship, AE-29, was commissioned in May 1971 and decommissioned in August 1999.

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