Glacier Peak
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Glacier Peak or Dakobed (known in the Sauk-Suiattle dialect of the
Lushootseed Lushootseed (txʷəlšucid, dxʷləšúcid), also Puget Salish, Puget Sound Salish or Skagit-Nisqually, is a language made up of a dialect continuum of several Salish tribes of modern-day Washington state. Lushootseed is one of the Coast Salish ...
language as "Tda-ko-buh-ba" or "Takobia") is the most isolated of the five major
stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and per ...
es (composite volcanoes) of the
Cascade Volcanic Arc The Cascade Volcanoes (also known as the Cascade Volcanic Arc or the Cascade Arc) are a number of volcanoes in a volcanic arc in western North America, extending from southwestern British Columbia through Washington and Oregon to Northern Califo ...
in the
U.S The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
state of
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...
. Located in the
Glacier Peak Wilderness Glacier Peak Wilderness is a , , wilderness area located within portions of Chelan, Snohomish, and Skagit counties in the North Cascades of Washington. The area lies within parts of Wenatchee National Forest and Mount Baker National Forest a ...
in
Mount Baker–Snoqualmie National Forest The Mount Baker–Snoqualmie National Forest in Washington is a National Forest extending more than along the western slopes of the Cascade Range from the Canada–US border to the northern boundary of Mount Rainier National Park. Administered ...
, the volcano is visible from the west in
Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...
, and from the north in the higher areas of eastern suburbs of Vancouver such as
Coquitlam Coquitlam ( ) is a city in the Lower Mainland of British Columbia, Canada. Mainly suburban, Coquitlam is the List of cities in British Columbia, sixth-largest city in the province, with a population of 148,625 in 2021, and one of the 21 municipa ...
,
New Westminster New Westminster (colloquially known as New West) is a city in the Lower Mainland region of British Columbia, Canada, and a member municipality of the Metro Vancouver Regional District. It was founded by Major-General Richard Moody as the capita ...
and
Port Coquitlam Port Coquitlam ( ) is a city in British Columbia, Canada. Located east of Vancouver, it is on the north bank of the confluence of the Fraser River and the Pitt River. Coquitlam borders it on the north, the Coquitlam River borders it on the west, ...
. 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 Snohomish County () is a county located in the U.S. state of Washington. With a population of 827,957 as of the 2020 census, it is the third-most populous county in Washington, after nearby King and Pierce counties, and the 75th-most populous ...
, the volcano is only northeast of downtown Seattle. From locations in northern Seattle and northward, Glacier Peak is closer than the more famous
Mount Rainier Mount Rainier (), indigenously known as Tahoma, Tacoma, Tacobet, or təqʷubəʔ, is a large active stratovolcano in the Cascade Range of the Pacific Northwest, located in Mount Rainier National Park about south-southeast of Seattle. With a s ...
(Tahoma), but as Glacier Peak is set farther into the Cascades and almost 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 The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
epoch, about one million years ago, and since the most recent
ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...
, 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.


Geology

Remnants of past (prehistoric)
lava dome In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on ...
s are main components of the summit of the volcano, in addition to its false summit, Disappointment Peak. Past
pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of bu ...
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. On its western flank, the volcano also has a
lahar A lahar (, from jv, ꦮ꧀ꦭꦲꦂ) 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. Lahars are extreme ...
, or mudflow deposit, which runs for about 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 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 Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...
; and continued for into the Sauk River. 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, located by the mountain, there is a lahar at least thick, containing pyroclastic flow deposits and other mudflows. However, this large mudflow is part of a concentration of past incidents at the volcano that spans the Dusty and
Chocolate Creek Chocolate is a food made from roasted and ground cacao seed kernels that is available as a liquid, solid, or paste, either on its own or as a flavoring agent in other foods. Cacao has been consumed in some form since at least the Olmec civi ...
. In the area at least of lithic debris are contained.
Tephra Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they rem ...
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. On the mountain, about up, are three additional
cinder cone A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions o ...
s — one at the head of White Chuck River, one at
Dishpan Gap Dishpan Gap is a cinder cone in Chelan County of Washington, US. Located near Glacier Peak and White Chuck Cinder Cone, its elevation is approximately . Known for his creative naming of natural features in the Cascade Range, forest supervisor A ...
, and one near Indian Pass. The volcano has also caused thermal events such as
hot spring A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...
s. There were three hot springs on the mountain: Gamma, Kennedy, and Sulphur, but Kennedy Hot Springs was destroyed and buried in a slide.


Tectonic setting

The volcano is located in
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...
, and is one of the five major stratovolcanoes there. Situated in the
Cascade Volcanic Arc The Cascade Volcanoes (also known as the Cascade Volcanic Arc or the Cascade Arc) are a number of volcanoes in a volcanic arc in western North America, extending from southwestern British Columbia through Washington and Oregon to Northern Califo ...
, the volcano was created by
subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...
of the oceanic Juan de Fuca Plate under the
North American Plate The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...
. Convergence between the two continues at a rate of 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.


History

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". In 1898 the volcano was finally documented on a map. 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 The Northern Pacific Railway was a transcontinental railroad that operated across the northern tier of the western United States, from Minnesota to the Pacific Northwest. It was approved by Congress in 1864 and given nearly of land grants, whic ...
searching for possible railroad routes when he saw it in 1870.


Eruptive history

Despite its elevation of , 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 above the underlying ridge. Another Cascade Arc volcano with similar
geomorphology Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or n ...
is the
Mount Meager massif The Mount Meager massif is a group of volcanic peaks in the of the Coast Mountains in southwestern British Columbia, Canada. Part of the Cascade Volcanic Arc of western North America, it is located north of Vancouver at the northern end of the ...
in southwestern
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
, Canada, which is situated on a ridge of nonvolcanic, crystalline and
metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...
. Of the five major volcanoes in Washington, only Glacier Peak and
Mount St. Helens Mount St. Helens (known as Lawetlat'la to the indigenous Cowlitz people, and Loowit or Louwala-Clough to the Klickitat) is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United St ...
have had large eruptions in the past 15,000 years. Since both volcanoes generate magma of
dacitic Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite ...
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 Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they rem ...
, which in its simplest form, is
ash Ash or ashes are the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non- gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash ...
.
Tephrochronology 250px, Tephra horizons in south-central Iceland. The thick and light coloured layer at the height of the volcanologist's hands is rhyolitic tephra from Hekla. Tephrochronology is a Geochronology, geochronological technique that uses discrete la ...
and
radiocarbon dating Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was dev ...
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 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 eru ...
. They were characterized mainly by a central vent eruption, followed by an explosive eruption. These eruptions varied in outcome; some produced
lahars A lahar (, from jv, ꦮ꧀ꦭꦲꦂ) 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. Lahars are extremel ...
, some
pyroclastic flows A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...
, and others
lava dome In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on ...
s. 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 The Stillaguamish River is a river in the northwestern region of the U.S. state of Washington. It is mainly composed of two forks, the longer North Fork Stillaguamish () and the South Fork Stillaguamish. The two forks join near Arlington. From ...
(at that time an outlet of the Sauk River) and
Skagit River 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& ...
s. In Arlington, 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 Puget Sound ( ) is a sound of the Pacific Northwest, an inlet of the Pacific Ocean, and part of the Salish Sea. It is located along the northwestern coast of the U.S. state of Washington. It is a complex estuarine system of interconnected ma ...
. 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 near Chelan and near
Missoula, Montana Missoula ( ; fla, label=Salish language, Séliš, Nłʔay, lit=Place of the Small Bull Trout, script=Latn; kut, Tuhuⱡnana, script=Latn) is a city in the U.S. state of Montana; it is the county seat of Missoula County, Montana, Missoula Cou ...
. The table below shows the three largest eruptions from this sequence. 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.


Hazards

The risk of an eruption in any given year is currently estimated as 1 in 1,000. When lahars reach populated areas, they can bury structures and people. An example was the
Armero tragedy The Armero tragedy ( es, Tragedia de Armero, links=no ) occurred following the eruption of the Nevado del Ruiz stratovolcano in Tolima, Colombia, on November 13, 1985. The volcano's eruption after 69 years of dormancy caught nearby towns unawar ...
at
Nevado del Ruiz The Nevado del Ruiz (), also known as La Mesa de Herveo ( en, Mesa of Herveo, the name of the nearby town) is a volcano on the border of the departments of Caldas and Tolima in Colombia, about west of the capital city Bogotá. It is a strat ...
where 23,000 died from an enormous mudflow. Lahars from Glacier Peak pose a similar threat to the small communities of Darrington and
Concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...
and a lesser threat to the larger and rapidly growing towns of
Mount Vernon Mount Vernon is an American landmark and former plantation of Founding Father, commander of the Continental Army in the Revolutionary War, and the first president of the United States George Washington and his wife, Martha. The estate is on ...
and
Burlington Burlington may refer to: Places Canada Geography * Burlington, Newfoundland and Labrador * Burlington, Nova Scotia * Burlington, Ontario, the most populous city with the name "Burlington" * Burlington, Prince Edward Island * Burlington Bay, no ...
, as well as other communities along the lower Skagit and Stillaguamish Rivers. A 2005 study conducted by the
United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
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".


Climate


Glaciers

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 The Little Ice Age (LIA) was a period of regional cooling, particularly pronounced in the North Atlantic region. It was not a true ice age of global extent. The term was introduced into scientific literature by François E. Matthes in 1939. Ma ...
to the 1958 positions was . 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 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 . Milk Lake Glacier, on the north flank of the mountain, melted away altogether in the 1990s.


Recreation

The
Pacific Crest Trail The Pacific Crest Trail (PCT), officially designated as the Pacific Crest National Scenic Trail, is a long-distance hiking and equestrian trail closely aligned with the highest portion of the Cascade and Sierra Nevada mountain ranges, which lie ...
passes near Glacier Peak. The
Suiattle River The Suiattle River is a river in the U.S. state of Washington. Course The Suiattle River originates from the Suiattle Glacier on the east slopes of Glacier Peak in the Cascade Range. It flows generally northwest to join the Sauk River north of ...
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. The first recorded person to climb the mountain was Thomas Gerdine, along with a group of
United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
scientists, Sam Strom, A. H. Dubor, and Darcy Bard, in 1897. The climb is Alpine Grade I or II. The easiest ski route is about 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.


Cultural references

The Seattle-based composer, Alan Hovhaness, dedicated his Symphony no.66 as "Hymn to Glacier Peak": see Symphony no.66 (Hovhaness).


See also

*
List of mountain peaks of North America This article comprises three sortable tables of major mountain peaksThis article defines a significant summit as a summit with at least of topographic prominence, and a major summit as a summit with at least of topographic prominence. All ...
**
List of mountain peaks of the United States This article comprises three sortable tables of major mountain peaksThis article defines a significant summit as a summit with at least of topographic prominence, and a major summit as a summit with at least of topographic prominence. All su ...
***
List of mountain peaks of Washington (state) This article comprises three sortable tables of major mountain peaksThis article defines a significant summit as a summit with at least of topographic prominence, and a major summit as a summit with at least of topographic prominence. All s ...
****
List of highest points in Washington by county This is a list of highest points in the U.S. state of Washington, in alphabetical order by county. References Sources *{{cite book, title=County high points: For all western and northeastern states , last=Martin, first=Andy, publisher=Old Adi ...
*
List of Ultras of the United States The following sortable table comprises the 200 most topographically prominent mountain peaks of the United States of America. The summit of a mountain or hill may be measured in three principal ways: #The topographic elevation of a summit me ...
*
List of volcanoes in the United States A list of volcanoes in the United States and its territories. Alaska American Samoa Arizona California Colorado Hawaii /[./[Https://www.sci.news/geology/puhahonu-shield-volcano-08435.html Puhahonu ...


References


External links


Glacier Peak on Ski Mountaineer.com
* *

Photographic albums and text documenting the Mountaineers official annual outings undertaken by club members from 1907 to 1951, primarily on the Olympic Peninsula, in Mount Rainier National Park and on Glacier Peak. {{Good article North American 3000 m summits Stratovolcanoes of the United States Cascade Range Mountains of Washington (state) Volcanoes of Washington (state) VEI-5 volcanoes [ ategory:Subduction volcanoes Cascade Volcanoes North Cascades of Washington (state) Landforms of Snohomish County, Washington Mountains of Snohomish County, Washington Mount Baker-Snoqualmie National Forest Religious places of the indigenous peoples of North America Pleistocene stratovolcanoes Holocene stratovolcanoes