Glacier Peak | |
---|---|
Dakobed Takobia | |
Highest point | |
Elevation | 10,525+ ft (3,207+ m) NAVD 88 [1] |
Prominence | 7,498 ft (2,285 m) [1] |
Listing | |
Coordinates | 48°06′43″N121°06′51″W / 48.11194°N 121.11417°W [1] [2] |
Geography | |
Location | Snohomish County, Washington, U.S. |
Parent range | Cascade Range |
Topo map | USGS Glacier Peak East |
Geology | |
Rock age | Pleistocene |
Mountain type | Stratovolcano [3] |
Volcanic arc | Cascade Volcanic Arc [3] |
Last eruption | 1700 [3] |
Climbing | |
First ascent | 1898 by Thomas Gerdine and party [4] |
Easiest route | Rock/ice climb on Sitkum Glacier |
Glacier Peak or Dakobed (known in the Sauk-Suiattle dialect of the Lushootseed language as "Tda-ko-buh-ba" or "Takobia" [5] ) is the most isolated of the five major stratovolcanoes (composite volcanoes) of the Cascade Volcanic Arc in the U.S state of Washington. Located in the Glacier Peak Wilderness in Mount Baker–Snoqualmie National Forest, the volcano is visible from the west in Seattle, and from the north in the higher areas of eastern suburbs of Vancouver such as Coquitlam, New Westminster and Port Coquitlam. The volcano is the fourth tallest peak in Washington state, and not as much is known about it compared to other volcanoes in the area. Local Native Americans have recognized Glacier Peak and other Washington volcanoes in their histories and stories. When American explorers reached the region, they learned basic information about surrounding landforms, but did not initially understand that Glacier Peak was a volcano. Positioned in Snohomish County, the volcano is only 70 miles (110 km) northeast of downtown Seattle. From locations in northern Seattle and northward, Glacier Peak is closer than the more famous Mount Rainier (Tahoma), but as Glacier Peak is set farther into the Cascades and almost 4,000 feet (1,200 m) shorter, it is much less noticeable than Mount Rainier.
Glacier Peak is one of the most active of Washington's volcanoes. The volcano formed during the Pleistocene epoch, about one million years ago, and since the most recent ice age, it has produced some of the largest and most explosive eruptions in the state. When continental ice sheets retreated from the region, Glacier Peak began to erupt regularly, erupting explosively five times in the past 3,000 years. It has erupted repeatedly during at least six periods; two of these eruptions have been among the largest in Washington.
Remnants of past (prehistoric) lava domes are main components of the summit of the volcano, in addition to its false summit, Disappointment Peak. Past pyroclastic flow deposits are easily visible in river valleys near the volcano, likely caused by lava dome collapse, along with ridges found east of the summit consisting of ash cloud remains. [6] On its western flank, the volcano also has a lahar, or mudflow deposit, which runs for about 22 miles (35 km) into the White Chuck River Valley around 14,000 years ago. Ten other pyroclastic flow deposits are visible, all identified as relatively 10,000 years old. There is also a considerably newer mudflow, about 5,500 years old, which covers an area of 9.3 mi (15 km) between the same river valley, along with two small incidents both under 3,000 years old. Another lahar, of unidentified age, was rich in oxyhornblende dacite; and continued for 30 km (19 mi) into the Sauk River. [7]
There are also ash cloud deposits on the opposite eastern flank of the volcano. Studies of the mountain have to date been unable to find any correspondence with pyroclastic flows, but several past mudflows have been identified. In the Dusty Creek valley, which runs east from the mountain, there is a lahar at least 98 ft (30 m) thick, containing pyroclastic flow deposits and other mudflows. However, this large mudflow is part of a 980-foot-thick (300 m) concentration of past incidents at the volcano that spans the Dusty Creek and Chocolate Creek valleys. The area contains at least 2.4 cubic miles (10 km3) of lithic debris. [7] Tephra deposits are for the most part constrained to the left flank of the volcano, and at least nine past incidents have been identified. These form several layers of tephra constructing the mountain. Smaller eruptions involving tephra occurred between 6,900 and 5,500 years ago, again between 3,450 and 200 years ago, and as recently as 316 to 90 years ago. [7]
On the mountain, about 5,900 ft (1,800 m) up, are three additional cinder cones — one at the head of White Chuck River, one at Dishpan Gap, and one near Indian Pass. [8] The volcano has also created thermal features such as hot springs. There were three hot springs on the mountain: Gamma, Kennedy, and Sulphur, [3] but Kennedy Hot Springs was destroyed and buried in a slide. [9]
The volcano is located in Washington, and is one of the five major stratovolcanoes there. Situated in the Cascade Volcanic Arc, the volcano was created by subduction of the oceanic Juan de Fuca Plate under the North American Plate. [10] Convergence between the two continues at a rate of 1.6 inches (4 cm) per year. This range has been volcanically active for about 36 million years, and the rocks that make up its volcanoes are between 55 and 42 million years old. Eruptions within the range are irregular and do not occur all at once. In an attempt to organize the volcanoes by age, scientists typically divide them into the High Cascades, younger volcanoes, and the Western Cascades, consisting of the older volcanoes. However, the vents in Washington are all of different ages so none of its volcanoes are included in either of the sections. [11]
Around the area, there were many Native Americans, and along with other Washington volcanoes, the mountain was recognized by them as a spirit. When European-American explorers reached the area, they learned about the mountain, though only partially, through local legends. Although the local people described Glacier Peak as a vital part of their storytelling and beliefs, when other volcanoes in the area were mapped, Glacier Peak was left out. In 1850 natives mentioned the volcano to naturalist George Gibbs saying that the volcano had once "smoked". [6] In 1898 the volcano was finally documented on a map. [6]
Native Americans also used the area around the Cascades for their agriculture, leading them to often congregate in the region. As a result, gold miners eventually reached the area in the 1870s–1890s, searching for resources and rich land. The first white man recorded to observe the mountain—Daniel Lindsley—was an employee of the Northern Pacific Railroad Company searching for possible railroad routes when he saw it in 1870. [12]
Despite its elevation of 10,541 feet (3,213 m), Glacier Peak is a small stratovolcano. Its relatively high summit is a consequence of its location atop a high ridge, but its volcanic portion extends only 1,600–3,200 feet (500–1,000 m) above the underlying ridge. [13] Another Cascade Arc volcano with similar geomorphology is the Mount Meager massif in southwestern British Columbia, Canada, which is situated on a 1,300 ft (400 m) ridge of nonvolcanic, crystalline and metamorphic rock. [14]
Of the five major volcanoes in Washington, only Glacier Peak and Mount St. Helens have had large eruptions in the past 15,000 years. Since both volcanoes generate magma of dacitic origin, the viscous magma builds up since it cannot flow through the eruptive vent. Gradually, the pressure grows, culminating in an explosion that ejects materials such as tephra, which in its simplest form, is ash. [6]
Tephrochronology and radiocarbon dating indicate that Glacier Peak eruptions occurred in 1700 AD ± 100 years, 1300 AD ± 300 years, 900 AD ± 50 years, 200 AD ± 50 years, 850 BC, 3150 BC, and in 3550 BC. The Volcanic Explosivity Index (VEI) for three of these was 2 to 4, small compared to the 5 of the 1980 eruption of Mount St. Helens. They were characterized mainly by a central vent eruption, followed by an explosive eruption. These eruptions varied in outcome; some produced lahars, some pyroclastic flows, and others lava domes. [3] The volcano has had one eruption with a VEI of 2, one with a VEI of 4, and possibly another with a VEI of 3. [15]
A little more than 13,000 years ago, a sequence of nine tephra eruptions occurred within a period of less than a few hundred years. Associated with these eruptions were pyroclastic flows. Mixed with snow, ice and water, these formed lahars that raced into three nearby rivers, filling their valleys with deep deposits. Subsequently, the mudflows drained into both the North Fork of the Stillaguamish River (at that time an outlet of the Sauk River) and Skagit Rivers. In Arlington, 60 miles (97 km) downstream, lahars deposited seven feet of sediment. Subsequent erosion of lahar deposits near Darrington led to the current river system with the Stillaguamish River separated from the Sauk/Skagit Rivers. Lahar debris was deposited along both the Skagit and Stillaguamish Rivers all the way to Puget Sound. A small portion of the erupted tephra was deposited locally. However, most of the tephra reached higher levels of the atmosphere, and was transported by the wind hundreds of miles. Deposits from this congregation were as thick as 1 foot (0.30 m) near Chelan and 0.3 inches (7.6 mm) near Missoula, Montana. [6] The table below shows the three largest eruptions from this sequence. [16]
Unit Name | DRE Volume | Bulk Deposit Volume | Plume Height |
---|---|---|---|
Layer B | 2.1 km3 (0.50 cu mi) | 6.5 km3 (1.6 cu mi) | 31 km (19 mi) |
Layer M | 0.4 km3 (0.096 cu mi) | 1.1 km3 (0.26 cu mi) | N/A |
Layer G | 1.9 km3 (0.46 cu mi) | 6.0 km3 (1.4 cu mi) | 32 km (20 mi) |
Since these events, Glacier Peak has produced several lahars. The largest mudflows were 5,900 and 1,800 years ago and were associated with dome-building eruptions. In both cases, the lahars traveled down the Skagit River to Puget Sound. [6]
The risk of an eruption in any given year is currently estimated as 1 in 1,000. [17] As of 2018 [update] , Glacier Peak is classified as one of the 18 most dangerous volcanoes in the United States. [18]
When lahars reach populated areas, they can bury structures and people. An example was the Armero tragedy at Nevado del Ruiz where 23,000 died from an enormous mudflow. Lahars from Glacier Peak pose a similar threat to the small communities of Darrington, Arlington, and Concrete with a lesser threat to the larger and rapidly growing towns of Mount Vernon and Burlington, as well as other communities along the lower Skagit and Stillaguamish Rivers. [6] A 2005 study conducted by the United States Geological Survey identified nine Cascade volcanoes, including Glacier Peak, as "very-high-threat volcanoes with inadequate monitoring". At the time of the study, only one seismometer was installed on Glacier Peak that had not "worked in two years". [19] As of 2023 [update] , the PNSN still operates only one seismometer on Glacier Peak. [20]
In 2018, the USGS applied to add four more stations, but regulations protecting federal wilderness areas prohibit the use of helicopters that are needed to transport materials; advocacy groups opposed an exemption for the project and filed objections. [21] [22] In 2019, Congress passed the National Volcano Early Warning and Monitoring System Act to authorize more monitoring stations, but did not include funding to construct them. [23] Permits were granted by the U.S. Forest Service in June 2022. [24]
Climate data for Glacier Peak Summit. 1991-2020 | |||||||||||||
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Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
Mean daily maximum °F (°C) | 21.1 (−6.1) | 20.5 (−6.4) | 21.8 (−5.7) | 26.2 (−3.2) | 35.0 (1.7) | 41.3 (5.2) | 51.4 (10.8) | 51.9 (11.1) | 46.4 (8.0) | 35.8 (2.1) | 24.2 (−4.3) | 19.6 (−6.9) | 32.9 (0.5) |
Daily mean °F (°C) | 16.0 (−8.9) | 14.0 (−10.0) | 14.1 (−9.9) | 17.2 (−8.2) | 25.1 (−3.8) | 30.8 (−0.7) | 39.4 (4.1) | 40.1 (4.5) | 35.3 (1.8) | 26.8 (−2.9) | 18.5 (−7.5) | 14.8 (−9.6) | 24.3 (−4.3) |
Mean daily minimum °F (°C) | 10.8 (−11.8) | 7.5 (−13.6) | 6.4 (−14.2) | 8.3 (−13.2) | 15.2 (−9.3) | 20.2 (−6.6) | 27.4 (−2.6) | 28.2 (−2.1) | 24.2 (−4.3) | 17.8 (−7.9) | 12.9 (−10.6) | 9.9 (−12.3) | 15.7 (−9.1) |
Average precipitation inches (mm) | 13.78 (350) | 10.65 (271) | 11.26 (286) | 6.59 (167) | 4.33 (110) | 3.33 (85) | 1.83 (46) | 2.27 (58) | 4.06 (103) | 11.31 (287) | 16.43 (417) | 16.18 (411) | 102.02 (2,591) |
Average dew point °F (°C) | 8.6 (−13.0) | 5.3 (−14.8) | 4.1 (−15.5) | 4.5 (−15.3) | 10.7 (−11.8) | 15.8 (−9.0) | 19.4 (−7.0) | 19.2 (−7.1) | 16.0 (−8.9) | 13.1 (−10.5) | 10.3 (−12.1) | 8.4 (−13.1) | 11.3 (−11.5) |
Source: PRISM Climate Group [25] |
Eleven significant glaciers cover Glacier Peak. When C.E. Rusk first saw these glaciers in 1906 they were beginning to retreat, but were still very advanced. The average retreat of Glacier Peak glaciers from the Little Ice Age to the 1958 positions was 5,381 feet (1,640 m). Richard Hubley noted that North Cascade glaciers began to advance in the early 1950s, after 30 years of rapid retreat. The advance was in response to a sharp rise in winter precipitation and a decline in summer temperature beginning in 1944. Ten of the fifteen glaciers around Glacier Peak advanced, including all of the glaciers directly on the mountain's slopes. Advances of Glacier Peak glaciers ranged from 50 to 1,575 feet (15 to 480 m) and culminated in 1978. All eleven Glacier Peak glaciers that advanced during the 1950–79 period emplaced identifiable maximum advance terminal moraines. From 1984 to 2005, the average retreat of eight Glacier Peak glaciers from their recent maximum positions was 1,017 feet (310 m). Milk Lake Glacier, on the north flank of the mountain, melted away altogether in the 1990s. [26]
The Pacific Crest Trail passes near Glacier Peak. The Suiattle River crossing is a well-known feature on the Pacific Crest Trail (PCT) as it passes through the area. The Suiattle PCT crossing used to have a bridge crossing until it was flooded out by storms in late 2003. [27]
The first recorded person to climb the mountain was Thomas Gerdine, along with a group of United States Geological Survey scientists, Sam Strom, A. H. Dubor, and Darcy Bard, in 1897. [4] The climb is Alpine Grade I or II. [28]
The easiest ski route is about 5 miles (8.0 km) of walking along the White Chuck River Trail (Forest Service Trail No. 643) and up the Sitkum Glacier. The trail is reached via Forest Service Road No. 23. The Sitkum Glacier ski route is rated blue to black diamond for both the ascent and the descent. [29]
The Seattle-based composer, Alan Hovhaness, dedicated his Symphony no.66 as "Hymn to Glacier Peak": see Symphony no.66 (Hovhaness).
The non-fiction book Encounters with the Archdruid by John McPhee, which portrays the environmental advocacy of David Brower, devotes the first of its three main sections to a conflict over mineral prospecting around Glacier Peak.
Mount Baker, also known as Koma Kulshan or simply Kulshan, is a 10,781 ft (3,286 m) active glacier-covered andesitic stratovolcano in the Cascade Volcanic Arc and the North Cascades of Washington State in the United States. Mount Baker has the second-most thermally active crater in the Cascade Range after Mount St. Helens. About 30 miles (48 km) due east of the city of Bellingham, Whatcom County, Mount Baker is the youngest volcano in the Mount Baker volcanic field. While volcanism has persisted here for some 1.5 million years, the current volcanic cone is likely no more than 140,000 years old, and possibly no older than 80–90,000 years. Older volcanic edifices have mostly eroded away due to glaciation.
Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It lies 52 miles (83 km) northeast of Portland, Oregon, and 98 miles (158 km) south of Seattle. Mount St. Helens takes its English name from that of the British diplomat Alleyne Fitzherbert, 1st Baron St Helens, a friend of explorer George Vancouver who surveyed the area in the late 18th century. The volcano is part of the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire.
A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and explosive eruptions. Some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and solidifies before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high to intermediate levels of silica, with lesser amounts of less viscous mafic magma. Extensive felsic lava flows are uncommon, but can travel as far as 8 km (5 mi).
A lahar is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley.
Nevado del Ruiz, also known as La Mesa de Herveo is a volcano on the border of the departments of Caldas and Tolima in Colombia, being the highest point of both. It is located about 130 km (81 mi) west of the capital city Bogotá. It is a stratovolcano composed of many layers of lava alternating with hardened volcanic ash and other pyroclastic rocks. Volcanic activity at Nevado del Ruiz began about two million years ago, during the Early Pleistocene or Late Pliocene, with three major eruptive periods. The current volcanic cone formed during the present eruptive period, which began 150,000 years ago.
The Lassen volcanic area presents a geological record of sedimentation and volcanic activity in and around Lassen Volcanic National Park in Northern California, U.S. The park is located in the southernmost part of the Cascade Mountain Range in the Pacific Northwest region of the United States. Pacific Oceanic tectonic plates have plunged below the North American Plate in this part of North America for hundreds of millions of years. Heat and molten rock from these subducting plates has fed scores of volcanoes in California, Oregon, Washington and British Columbia over at least the past 30 million years, including these in the Lassen volcanic areas.
Lassen Peak, commonly referred to as Mount Lassen, is a 10,457 ft (3,187 m) lava dome volcano in Lassen Volcanic National Park in Northern California. Located in the Shasta Cascade region above the northern Sacramento Valley, it is the southernmost active volcano in the Cascade Range of the Western United States, and part of the Cascade Volcanic Arc stretching from southwestern British Columbia to northern California. It supports many flora and fauna among its diverse habitats, which reach high elevations and are subject to frequent snowfall.
Mount Jefferson is a stratovolcano in the Cascade Volcanic Arc, part of the Cascade Range in the U.S. state of Oregon. The second highest mountain in Oregon, it is situated within Linn County, Jefferson County, and Marion County and forms part of the Mount Jefferson Wilderness. Due to the ruggedness of its surroundings, the mountain is one of the hardest volcanoes to reach in the Cascades. It is also a popular tourist destination despite its remoteness, with recreational activities including hiking, backpacking, mountaineering, and photography. Vegetation at Mount Jefferson is dominated by Douglas fir, silver fir, mountain hemlock, ponderosa pine, lodgepole pine, and several cedar species. Carnivores, insectivores, bats, rodents, deer, birds, and various other species inhabit the area.
Mount Thielsen, is an extinct shield volcano in the Oregon High Cascades, near Mount Bailey. Because eruptive activity ceased 250,000 years ago, glaciers have heavily eroded the volcano's structure, creating precipitous slopes and a horn-like peak. The spire-like shape of Thielsen attracts lightning strikes and creates fulgurite, an unusual mineral. The prominent horn forms a centerpiece for the Mount Thielsen Wilderness, a reserve for recreational activities such as skiing and hiking. Thielsen is one of Oregon's Matterhorns.
Mount Mazama is a complex volcano in the western U.S. state of Oregon, in a segment of the Cascade Volcanic Arc and Cascade Range. The volcano is in Klamath County, in the southern Cascades, 60 miles (97 km) north of the Oregon–California border. Its collapse, due to the eruption of magma emptying the underlying magma chamber, formed a caldera that holds Crater Lake. Mount Mazama originally had an elevation of 12,000 feet (3,700 m), but following its climactic eruption this was reduced to 8,157 feet (2,486 m). Crater Lake is 1,943 feet (592 m) deep, the deepest freshwater body in the U.S. and the second deepest in North America after Great Slave Lake in Canada.
Three Fingered Jack is a summit of a shield volcano of the Cascade Range in the U.S. state of Oregon. Formed during the Pleistocene epoch, the mountain consists mainly of basaltic andesite lava and was heavily glaciated in the past. While other Oregon volcanoes that were heavily glaciated—such as Mount Washington and Mount Thielsen—display eroded volcanic necks, Three Fingered Jack's present summit is a comparatively narrow ridge of loose tephra supported by a dike only 10 feet (3.0 m) thick on a generally north–south axis. Glaciation exposed radiating dikes and plugs that support this summit. The volcano has long been inactive and is highly eroded.
On March 27, 1980, a series of volcanic explosions and pyroclastic flows began at Mount St. Helens in Skamania County, Washington, United States. A series of phreatic blasts occurred from the summit and escalated until a major explosive eruption took place on May 18, 1980, at 8:32 am. The eruption, which had a volcanic explosivity index of 5, was the first to occur in the contiguous United States since the much smaller 1915 eruption of Lassen Peak in California. It has often been considered the most disastrous volcanic eruption in U.S. history.
Spirit Lake is a lake in Skamania County, Washington, United States, located north of Mount St. Helens. It was a popular tourist destination for many years until Mount St. Helens erupted in 1980. Previously there had been six camps on the shore of Spirit Lake: Boy Scout, the Girl Scout Camp at Spirit Lake, two YMCA camps, Harmony Fall Lodge, and another for the general public. There were also several lodges accessible to visitors, including Spirit Lake Lodge and Mt. St. Helens Lodge. The latter was owned and operated by Harry R. Truman, a noted victim of the volcano's 1980 eruption.
The Skagit River is a river in southwestern British Columbia in Canada and northwestern Washington in the United States, approximately 150 mi (240 km) long. The river and its tributaries drain an area of 1.7 million acres (690,000 hectares) of the Cascade Range along the northern end of Puget Sound and flows into the sound.
The Sauk River is a tributary of the Skagit River, approximately 45 miles (72 km) long, in northwestern Washington in the United States. It drains an area of the high Cascade Range in the watershed of Puget Sound north of Seattle. The river is a popular destination for fly fishing. It is a National Wild and Scenic River.
Broken Top is a glacially eroded complex stratovolcano. It lies in the Cascade Volcanic Arc, part of the extensive Cascade Range in the U.S. state of Oregon. Located southeast of the Three Sisters peaks, the volcano, residing within the Three Sisters Wilderness, is 20 miles (32 km) west of Bend, Oregon in Deschutes County. Eruptive activity stopped roughly 100,000 years ago, and erosion by glaciers has since reduced the volcano's cone to where its contents are exposed. There are two named glaciers on the peak, Bend and Crook Glacier.
The Mount Meager massif is a group of volcanic peaks in the Pacific Ranges of the Coast Mountains in southwestern British Columbia, Canada. Part of the Cascade Volcanic Arc of western North America, it is located 150 km (93 mi) north of Vancouver at the northern end of the Pemberton Valley and reaches a maximum elevation of 2,680 m (8,790 ft). The massif is capped by several eroded volcanic edifices, including lava domes, volcanic plugs and overlapping piles of lava flows; these form at least six major summits including Mount Meager which is the second highest of the massif.
The Cascade Volcanoes are a number of volcanoes in a volcanic arc in western North America, extending from southwestern British Columbia through Washington and Oregon to Northern California, a distance of well over 700 miles (1,100 km). The arc formed due to subduction along the Cascadia subduction zone. Although taking its name from the Cascade Range, this term is a geologic grouping rather than a geographic one, and the Cascade Volcanoes extend north into the Coast Mountains, past the Fraser River which is the northward limit of the Cascade Range proper.
The Suiattle River is a river in the northern Cascade Mountains of western Washington, United States. It is a tributary of the Sauk River and by extension the Skagit River. Its source is located between Suiattle Glacier and Honeycomb Glacier on Glacier Peak, at an elevation of around 7,000 ft (2,100 m) above sea level. It descends through a 60-mile (97 km) course, lying mainly within the Mount Baker–Snoqualmie National Forest. It meets the Sauk northeast of Darrington, Washington, at an elevation of 400 ft (120 m). Snowmelt from Chocolate and Dusty Glacier gives the river silty water, with a suspended load over twice that of the upper Sauk or adjacent White Chuck.
Mount Rainier, also known as Tahoma, is a large active stratovolcano in the Cascade Range of the Pacific Northwest in the United States. The mountain is located in Mount Rainier National Park about 59 miles (95 km) south-southeast of Seattle. With an officially recognized summit elevation of 14,410 ft (4,392 m) at the Columbia Crest, it is the highest mountain in the U.S. state of Washington, the most topographically prominent mountain in the contiguous United States, and the tallest in the Cascade Volcanic Arc.