Mount St. Helens
3,000 ft (1 km) steam plume on May 19, 1982
Elevation	8,365 feet (2,550 m)
Location	Washington, USA
Range	Cascade Range
Prominence	4,605 feet (1,404 m)
Coordinates	46°12′00.17″N 122°11′21.13″W / 46.2000472, -122.1892028Coordinates: 46°12′00.17″N 122°11′21.13″W / 46.2000472, -122.1892028
Topo map	USGS Mount St. Events 1535 - French explorer Jacques Cartier sets sail on his second voyage to North America with three ships 110 men and Year 1982 ( MCMLXXXII) was a Common year starting on Friday (link displays the 1982 Gregorian calendar) In topography a summit is a point on a surface which is higher in Elevation than all points immediately adjacent to Washington ( is a state in the Pacific Northwest region of the United States. The United States of America —commonly referred to as the A mountain range is a chain of Mountains bordered by highlands or separated from other mountains by passes or valleys A geographic coordinate system enables every location on the Earth to be specified in three coordinates using mainly a spherical coordinate system. A geographic coordinate system enables every location on the Earth to be specified in three coordinates using mainly a spherical coordinate system. A topographic map is a type of Map characterized by large-scale detail and quantitative representation of relief, usually using Contour lines in modern The United States Geological Survey ( USGS) is a scientific agency of the United States government. Helens
Type	Active stratovolcano
Volcanic arc/belt	Cascade Volcanic Arc
Age of rock	< 40,000 yrs
Last eruption	2004–2008 (ongoing)
First ascent	1853 by Thomas J. Dryer
Easiest route	Hike via south slope of volcano (closest area near eruption site)

Mount St. Mountains can be characterized in several ways Some mountains are Volcanoes and can be characterized by the type of lava and eruptive history A stratovolcano, also called a composite volcano is a tall conical Volcano composed of many layers of hardened Lava, Tephra, and Volcanic A volcanic arc is a chain of volcanic islands or Mountains formed by Plate tectonics as an oceanic Tectonic plate subducts under A volcanic belt is a large volcanically active region Other terms are used for smaller areas of activity such as volcanic fields Volcanic belts are found above zones 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 The geologic time scale is a chronologic schema (or idealized Model) relating Stratigraphy to time that is used by Geologists and other Plate tectonics and hotspots Divergent plate boundaries At the In Climbing, a first ascent (FA is the first modern recorded climb to reach the top of a Mountain, or the first to follow a particular Climbing route Thomas Jefferson Dryer (1808–1879 was a newspaper publisher Freemason, mountain climber, and Politician in the Western United States. A climbing route is a path by which a climber reaches the top of a Mountain, rock or ice wall Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. A stratovolcano, also called a composite volcano is a tall conical Volcano composed of many layers of hardened Lava, Tephra, and Volcanic Skamania County is a County located in the US state of Washington. Washington ( is a state in the Pacific Northwest region of the United States. The Pacific Northwest is a region in the northwest of North America (the term refers to the land not the ocean The United States of America —commonly referred to as the It is 96 miles (154 km) south of Seattle and 53 miles (85 km) northeast of Portland, Oregon. Portland is a city located in the Northwestern United States, near the Confluence of the Willamette and Columbia rivers Mount St. Helens takes its English name from the British diplomat Lord St Helens, a friend of explorer George Vancouver who made a survey of the area in the late 18th century. English is a West Germanic language originating in England and is the First language for most people in the United Kingdom, the United States The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Alleyne Fitzherbert 1st Baron St Helens (born Derby 1 March 1753, died London 19 February 1839) was a British diplomat Captain George Vancouver The mountain is located in the Cascade Range and is part of the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire that includes over 160 active volcanoes. 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 Plate tectonics and hotspots Divergent plate boundaries At the This volcano is well known for its ash explosions and pyroclastic flows. Volcanic ash consists of small Tephra, which are bits of pulverized rock and glass created by volcanic eruptions less than in diameter A pyroclastic flow (also known as a pyroclastic density current) is a common and devastating result of some volcanic eruptions.

Mount St. Helens is most famous for its catastrophic eruption on May 18, 1980,^[1] which was the deadliest and most economically destructive volcanic event in the history of the United States. The 1980 eruption of Mount St Helens, a volcano located in Washington state in the United States was a major volcanic eruption. Events 1152 - Henry II of England marries Eleanor of Aquitaine. Year 1980 ( MCMLXXX) was a Leap year starting on Tuesday (link displays the 1980 Gregorian calendar) Fifty-seven people were killed; 250 homes, 47 bridges, 15 miles (24 km) of railways, and 185 miles (300 km) of highway were destroyed. The eruption caused a massive debris avalanche, reducing the elevation of the mountain's summit from 9,677 feet (2,950 m) to 8,365 feet (2,550 m) and replacing it with a mile-wide (1. A landslide is a geological phenomenon which includes a wide range of ground movement such as rock falls deep failure of slopes and shallow debris flows which can occur 5 km-wide) horseshoe-shaped crater. A horseshoe is a U-shaped item made of metal or of modern synthetic materials nailed or glued to the Hooves of Horses and some other Draught ^[2] The debris avalanche was up to 0. 7 cubic miles (2. 9 km³) in volume. The Mount St. Helens National Volcanic Monument was created to preserve the volcano and allow for its aftermath to be scientifically studied. Mount St Helens National Volcanic Monument is a US National Monument that

As with most other volcanoes in the Cascade Range, Mount St. Helens is a large eruptive cone consisting of lava rock interlayered with ash, pumice, and other deposits. Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures Pumice is a textural term for a volcanic rock that is a solidified frothy lava composed of highly microvesicular glass Pyroclastic with very thin translucent The mountain includes layers of basalt and andesite through which several domes of dacite lava have erupted. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. For the extinct cephalopod genus see Andesites. Andesite (ˈændəsaɪt is an igneous, Volcanic rock, of intermediate In Volcanology, a lava dome or plug dome is a roughly circular Mound -shaped protrusion resulting from the slow eruption of Felsic Lava Dacite ( deɪsaɪt) is an igneous, volcanic rock with a high iron content The largest of the dacite domes formed the previous summit, and off its northern flank sat the smaller Goat Rocks dome. Both were destroyed in the 1980 eruption.

Mount St. Helens the day before the 1980 eruption, which removed much of the northern face of the mountain, leaving a large crater (caldera). A caldera is a cauldron-like volcanic feature formed by the collapse of land following a volcanic eruption

Mt. St. Helens in 2007. Viewed from Johnston Ridge Observatory.

Geographic setting and description

General

The view in 2002 from Climbers Bivouac

Mount St. Helens is 45 miles (72 km) west of Mount Adams, in the western part of the Cascade Range. Mount Adams is a potentially active Stratovolcano in the Cascade Range and the second-highest Mountain in the state of Washington These "sister and brother" volcanic mountains are approximately 50 miles (80 km) from Mount Rainier, the highest of Cascade volcanoes. Mount Rainier is an active Stratovolcano (also known as a composite volcano in Pierce County Washington, located southeast of Seattle, Washington Mount Hood, the nearest major volcanic peak in Oregon, is 60 miles (96 km) southeast of Mount St. Mount Hood (called Wy'east by the Multnomah tribe) is a Stratovolcano in the Cascade Volcanic Arc in northern Oregon ( is a state in the Pacific Northwest region of the United States. Helens.

Mount St. Helens is geologically young compared to the other major Cascade volcanoes. It formed only within the past 40,000 years, and the pre-1980 summit cone began rising about 2,200 years ago. ^[3] The volcano is considered the most active in the Cascades within the Holocene epoch (the last 10,000 or so years). The Holocene is a Geological epoch which began approximately 10000 years ago (about 8000 BC ^[4]

A view of St. Helens and the nearby area from space.

Prior to the 1980 eruption, Mount St. Helens was the fifth-highest peak in Washington. It stood out prominently from surrounding hills because of the symmetry and extensive snow and ice cover of the pre-1980 summit cone, earning it the nickname "Fuji-san of America" ("Mount Fuji of America"). is the highest Mountain in Japan at.An Active volcano that last erupted in 1707–08 it straddles the boundary of Shizuoka and ^[5] The peak rose more than 5,000 feet (1,525 m) above its base, where the lower flanks merge with adjacent ridges. The mountain is six miles (9. 6 km) across at its base, which is at an altitude of 4,400 feet (1,340 m) on the northeastern side and 4,000 feet (1,220 m) elsewhere. At the pre-eruption tree line, the width of the cone was four miles (6. The tree line or timberline is the edge of the habitat at which Trees are capable of growing 4 km).

Streams that originate on the volcano enter three main river systems: the Toutle River on the north and northwest, the Kalama River on the west, and the Lewis River on the south and east. A stream is a body of Water with a current, confined within a bed and stream-banks The Toutle River is a river in southwestern Washington State in the Pacific Northwest region of the United States The Lewis River is a tributary of the Columbia River, approximately long in southwestern Washington in the United States. The streams are fed by abundant rain and snow. The average annual rainfall is 140 inches (3. 6 m), and the snowpack on the mountain's upper slopes can reach 16 feet (4. 9 m). ^[6] The Lewis River is impounded by three dams for hydroelectric power generation. A dam is a barrier that divides waters. Dams generally serve the primary purpose of retaining water while other structures such as Floodgates, Levees Hydroelectricity is electricity generated by Hydropower, ie the production of power through use of the gravitational force of falling water The southern and eastern sides of the volcano drain into an upstream impoundment, the Swift Reservoir, which is directly south of the volcano's peak.

Phreatic eruption at the summit of Mount St. Helens, Washington in the spring of 1980.

Although Mount St. Helens is in Skamania County, Washington, the best access routes to the mountain run through Cowlitz County to the west. Cowlitz County is a County located in the US state of Washington. State Route 504, locally known as the Spirit Lake Memorial Highway, connects with the heavily traveled Interstate 5 at Exit 49, 34 miles (55 km) to the west of the mountain. State Route 504 (also known as the Spirit Lake Memorial Highway is a Highway that runs east from Castle Rock Washington for 52 miles to its present State Route 504 (also known as the Spirit Lake Memorial Highway is a Highway that runs east from Castle Rock Washington for 52 miles to its present Interstate 5 in Washington (I-5 is a highway in the US state of Washington that extends from its border with Oregon to its border with Canada That major north-south highway skirts the low-lying cities of Castle Rock, Longview and Kelso along the Cowlitz River, and passes through the Vancouver, Washington-Portland, Oregon metropolitan area less than 50 miles (80 km) to the southwest. * * * * * * * * * * * * * * * * * * * * * * Before adding any more images to this * * page please do carefully consider * * whether they would be mere decoration * * or actually improve Castle Rock, also known as Turokville or "The Canyon" is a city in Cowlitz County, Washington, United States. Longview is a city in Cowlitz County, Washington, United States. Kelso is a city in Cowlitz County, Washington, United States. The Cowlitz River is a River in the state of Washington in the United States, a Tributary of the Columbia River. Vancouver is a city on the north bank of the Columbia River in the U Portland is a city located in the Northwestern United States, near the Confluence of the Willamette and Columbia rivers A metropolitan area is a large population center consisting of a large Metropolis and its adjacent zone of influence or of more than one closely adjoining neighboring central The community nearest the volcano is Cougar, Washington, in the Lewis River valley 11 miles (18 km) south-southwest of the peak. Cougar is a former town and now unincorporated community, in Cowlitz County, Washington, United States. Gifford Pinchot National Forest surrounds Mount St. Gifford Pinchot Helens.

Crater Glacier and other new rock glaciers

Main article: Crater Glacier

During the winter of 1980–1981, a new glacier appeared. The Crater Glacier (also known as Tulutson Glacier) is a geologically young Glacier that is located on Mount Saint Helens, in the U "Glacial" and "Glaciation" redirect here For the geological periods see Glacial period. Now officially named Crater Glacier, it was formerly known as the Tulutson Glacier. The Crater Glacier (also known as Tulutson Glacier) is a geologically young Glacier that is located on Mount Saint Helens, in the U Shadowed by the crater walls and fed by heavy snowfall and repeated snow avalanches, it grew rapidly (46 feet or 14 m/year in thickness). By 2004, it covered about 0. 36 square mile (0. 93 km²), and was divided by the dome into a western and eastern lobe. Typically, by late summer, the glacier looks dark from rockfall from the crater walls and ash from eruptions. As of 2006, the ice had an average thickness of 328 feet (100 m) and a maximum of 656 feet (200 m), nearly as deep as the much older and larger Carbon Glacier of Mount Rainier. Carbon Glacier is located on the north slope of Mount Rainier in the U The ice is all post–1980, making the glacier very young geologically. However, the volume of the new glacier is about the same as all the pre–1980 glaciers combined. ^{[7][8][9][10][11]}

With the recent volcanic activity starting in 2004, the glacier lobes were pushed aside and upward by the growth of new volcanic domes. The surface of the glacier, once mostly uncrevassed, turned into a chaotic jumble of icefalls heavily criss-crossed with crevasses and seracs caused by movement of the crater floor. An icefall is a portion of some Glaciers characterized by rapid flow and a chaotic Crevassed surface A crevasse is a Fracture in a Glacier caused by a large Tensile stress at or near the glacier's surface A serac (originally from Swiss French sérac, a type of crumbly white Cheese) is a block or column of Ice formed by intersecting Crevasses ^[12] The new domes have almost separated the Crater Glacier into an eastern and western lobe. Despite the ongoing volcanic activity, the termini of the glacier have still advanced, with a slight advance on the western lobe and a more considerable advance on the more shaded eastern lobe. Due to the advance, two lobes of the glacier joined together in late-May 2008 and thus the glacier completely surrounds the lava domes. ^[12][13][14] In addition, since 2004, new glaciers have formed on the crater wall above Crater Glacier feeding rock and ice onto its surface below; there are two rock glaciers to the north of the eastern lobe of Crater Glacier. ^[15]

Human history

Importance to Native Americans

Traces of ancient campsites have been found in the Gifford Pinchot National Forest, which surrounds the monument. Gifford Pinchot Dating of these sites reveals that people have lived in this area for at least 6,500 years. ^[16] Throughout human history, Mount St. Helens eruptions have had a dramatic effect on the lives of local inhabitants. Work by archaeologists has shown that a massive eruption 3,500 years ago buried native settlements with a thick layer of pumice. Pumice is a textural term for a volcanic rock that is a solidified frothy lava composed of highly microvesicular glass Pyroclastic with very thin translucent As a result, people abandoned the area for nearly 2,000 years. ^[16] Later, members of the Cowlitz, Taidnapam, Klickitat, Upper Chinook, and Yakama tribes moved seasonally over the land, harvesting huckleberries and hunting salmon, elk, and deer. The Cowlitz are a group of Native American peoples from what is now western Washington state in the United States. The Cowlitz are a group of Native American peoples from what is now western Washington state in the United States. Chinookan refers to several groups of Native Americans in the Pacific Northwest region of the United States. The Confederated Tribes and Bands of the Yakama Nation, or simply Yakama Nation (formerly Yakima) is a Native American group with nearly 10000 enrolled Salmon is the common name for several species of Fish of the family Salmonidae. The elk, or wapiti ( Cervus canadensis) is one of the largest Species of Deer in the world and one of the largest Mammals in A deer is a Ruminant Mammal belonging to the family Cervidae. ^[16]

Indigenous American legends were inspired by the volcano's beauty.

Local legends

American Indian lore contains numerous legends to explain the eruptions of Mount St. For indigenous peoples in the United States other than Hawaii and Alaska see also Native Americans in the United States. Helens and other Cascade volcanoes. The most famous of these is the Bridge of the Gods legend told by the Klickitats. The original Bridge of the Gods was created during the eighteenth century by the Bonneville Slide, a major Landslide which Dammed the Columbia River In their tale, the chief of all the gods, Tyhee Saghalie and his two sons, Pahto (also called Klickitat) and Wy'east, traveled down the Columbia River from the Far North in search for a suitable area to settle. The Columbia River (known as ^[17]

They came upon an area that is now called The Dalles and thought they had never seen a land so beautiful. This page is about the Oregon town For the nearby geological formation The Dalles see Celilo Falls. The sons quarreled over the land, so to solve the dispute their father shot two arrows from his mighty bow—one to the north and the other to the south. Pahto followed the arrow to the north and settled there while Wy'east did the same for the arrow to the south. Saghalie then built Tanmahawis, the Bridge of the Gods, so his family could meet periodically. ^[17]

When the two sons of the Saghalie fell in love with a beautiful maiden named Loowit, she could not choose between them. The two young chiefs fought over her, burying villages and forests in the process. The area was devastated and the earth shook so violently that the huge bridge fell into the river, creating the cascades of the Columbia River Gorge. The Columbia River Gorge is a Canyon of the Columbia River in the Pacific Northwest of the United States. ^[18]

For punishment, Saghalie struck down each of the lovers and transformed them into great mountains where they fell. Wy'east, with his head lifted in pride, became the volcano known today as Mount Hood. Pahto, with his head bent toward his fallen love, was turned into Mount Adams. The fair Loowit became Mount St. Helens, known to the Klickitats as Louwala-Clough, which means "smoking or fire mountain" in their language (the Sahaptin called the mountain Loowit). The Sahaptin people are a Native American people that inhabited territory along the Columbia River. ^[19]

Exploration by Europeans

Royal Navy Commander George Vancouver and the officers of HMS Discovery made the Europeans' first recorded sighting of Mount St. The Royal Navy of the United Kingdom is the oldest of the British armed services (and is therefore known as the Senior Service) Captain George Vancouver The Voyage (See also Vancouver Expedition) Discovery was built for a voyage of exploration to the Southern whale fisheries Helens on May 19, 1792, while surveying the northern Pacific Ocean coast. Events 1535 - French explorer Jacques Cartier sets sail on his second voyage to North America with three ships 110 men and Year 1792 ( MDCCXCII) was a Leap year starting on Sunday (link will display the full calendar of the Gregorian calendar (or a Leap year The Pacific Ocean is the largest of the Earth 's Oceanic divisions Vancouver named the mountain for British diplomat Alleyne Fitzherbert, 1st Baron St Helens on October 20, 1792,^[19] as it came into view when the Discovery passed into the mouth of the Columbia River. Alleyne Fitzherbert 1st Baron St Helens (born Derby 1 March 1753, died London 19 February 1839) was a British diplomat Events 1740 - Maria Theresa takes the throne of Austria. France, Prussia, Bavaria and Saxony Year 1792 ( MDCCXCII) was a Leap year starting on Sunday (link will display the full calendar of the Gregorian calendar (or a Leap year

Years later, explorers, traders, and missionaries heard reports of an erupting volcano in the area. Geologists and historians determined much later that the eruption took place in 1800, marking the beginning of the 57-year-long Goat Rocks Eruptive Period (see geology section). ^[20] Alarmed by the "dry snow," the Nespelem tribe of northeastern Washington danced and prayed rather than collecting food and suffered during that winter from starvation. ^[20]

In late 1805 and early 1806, members of the Lewis and Clark Expedition spotted Mount St. Helens from the Columbia River but did not report either an ongoing eruption or recent evidence of one. ^[21] They did however report the presence of quicksand and clogged channel conditions at the mouth of the Sandy River near Portland, suggesting an eruption by Mount Hood sometime in the previous decades. Quicksand is a Colloid Hydrogel consisting of fine Granular matter (such as Sand or Silt) Clay, and The Sandy River is a tributary of the Columbia River in northwestern Oregon in the United States. Mount Hood (called Wy'east by the Multnomah tribe) is a Stratovolcano in the Cascade Volcanic Arc in northern

European settlement and use of the area

19th century photo of a fur trapper working in the Mount St. The activity of animal trapping has two separate but related meanings Helens area.

The area's first non-aboriginal inhabitants were European fur traders and trappers. The fur trade is a worldwide industry dealing in the acquisition and sale of animal Fur. Most of these men worked for the fur trading enterprise of the British-owned Hudson's Bay Company. ^[22] In the early 1890s, Ole' Peterson set up housekeeping at Cougar Flats, on the Upper Lewis River. ^[22] He was a true hermit—preferring to keep to himself, and enjoying the quiet solitude of nature. A hermit (from the Greek ἔρημος erēmos, signifying " Desert " "uninhabited" hence "desert-dweller" adjective "eremitic"

Also in the early 1890s, a 156-square mile (404 km²) mining district north of Spirit Lake was established. Spirit Lake is a Lake north of Mount St Helens in Washington State. By 1911, over 400 mining claims had been filed. ^[22] However, the minerals were never found in profitable quantities, and though much effort was spent in attempting to build a road or railroad into the district, by 1911, it was clear that there were no veins of precious minerals rich enough to offset the high transportation costs. ^[22]

James Dwight Dana was among the first geologists to view the volcano. James Dwight Dana (February 12 1813 &ndash April 14 1895 was an American Geologist, Mineralogist and Zoologist.

The first authenticated eyewitness report of a volcanic eruption was made in March 1835 by Dr. Meredith Gairdner, while working for the Hudson's Bay Company stationed at Fort Vancouver. Fort Vancouver was a 19th century fur trading outpost along the Columbia River that served as the headquarters of the Hudson's Bay Company in the company's ^[23] He sent an account to the Edinburgh New Philosophical Journal, which published his letter in January 1836. James Dwight Dana of Yale University, while sailing with the United States Exploring Expedition, saw the quiescent peak from off the mouth of the Columbia River in 1841. James Dwight Dana (February 12 1813 &ndash April 14 1895 was an American Geologist, Mineralogist and Zoologist. The United States Exploring Expedition was an exploring and surveying expedition of the Pacific Ocean ("the Southern Seas" conducted by the United States Navy from Another member of the expedition later described "cellular basaltic lavas" at the mountain's base. ^[24]

In late fall or early winter of 1842, nearby settlers and missionaries witnessed the so-called "Great Eruption. " This small-volume outburst created large ash clouds, and mild explosions followed for 15 years. ^[25] The eruptions of this period were likely phreatic (steam explosions). A Phreatic eruption, also called an ultravulcanian eruption, occurs when rising Magma makes contact with ground or surface water Uses A Steam engine uses the expansion of steam in order to drive a Piston or Turbine to perform Mechanical work. The Reverend Josiah Parrish in Champoeg, Oregon, witnessed Mount St. Reverend Josiah Lamberson Parrish (1806-1895 was an American missionary in Oregon Country and trustee of the Oregon Institute at its founding Champoeg (ʃæmˈpuːi sham-POO-ee or historically as sham poo' eg is a former town in the U Helens in eruption on November 22, 1842. Events 498 - Kofi Aseidu- After the death of Anastasius II, Symmachus is elected Pope in the Lateran Year 1842 ( MDCCCXLII) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian Calendar (or a Common Ash from this eruption may have reached The Dalles, Oregon, 48 miles (80 km) southeast of the volcano. This page is about the Oregon town For the nearby geological formation The Dalles see Celilo Falls. ^[4]

Mount St. Helens erupting at night. Painting by Paul Kane after his 1847 visit to the area. Paul Kane (September 3 1810 &ndash February 20 1871 was an Irish - Canadian painter famous for his paintings of First Nations peoples in the Canadian

In October 1843, future California governor Peter H. Burnett recounted a story of an aboriginal American man who badly burned his foot and leg in lava or hot ash while hunting for deer. California ( is a US state on the West Coast of the United States, along the Pacific Ocean. Peter Hardeman Burnett ( November 15, 1807 May 17, 1895) was an American politician and the first state Governor of California The likely apocryphal story went that the injured man sought treatment at Fort Vancouver, but the contemporary fort commissary steward, Napolean McGilvery, disclaimed knowledge of the incident. ^[26] British lieutenant Henry J. Warre sketched the eruption in 1845, and two years later Canadian painter Paul Kane created watercolors of the gently smoking mountain. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Paul Kane (September 3 1810 &ndash February 20 1871 was an Irish - Canadian painter famous for his paintings of First Nations peoples in the Canadian Warre's work showed erupting material from a vent about a third of the way down from the summit on the mountain's west or northwest side (possibly at Goat Rocks), and one of Kane's field sketches shows smoke emanating from about the same location. ^[27]

On April 17, 1857, the Republican, a Steilacoom, Washington newspaper, reported that "Mount St. Events 69 - After the First Battle of Bedriacum, Vitellius becomes Roman Emperor. Click here for Indian Rebellion of 1857 Year 1857 ( MDCCCLVII) was a Common year starting on Thursday (link will display the Steilacoom is a town in Pierce County, Washington, United States. Helens, or some other mount to the southward, is seen . . . to be in a state of eruption". ^[28] The lack of a significant ash layer associated with this event indicates that it was a small eruption. This was the first reported volcanic activity since 1854. ^[28]

Boats in Spirit Lake sometime before the 1980 eruption. Spirit Lake is a Lake north of Mount St Helens in Washington State.

Before the 1980 eruption, Spirit Lake offered year-round recreational activities. Spirit Lake is a Lake north of Mount St Helens in Washington State. In the summer there was boating, swimming, and camping, while in the winter there was skiing. Boating, the leisurely activity of traveling by Boat typically refers to the Recreational use of boats whether Power boats sail boats, or Swimming is the movement by humans or animals through Water, usually without artificial assistance Definition Camping describes a range of activities Survivalist campers set off with little more than their boots whereas Recreational vehicle travelers arrive equipped Snow skiing is a group of sports utilizing Skis as primary equipment

Human impact from the 1980 eruption

Ash from the eruption disrupted life for millions of people. Fifty-seven people died, and the economic cost was US$1 billion. The United States dollar ( sign: $; code: USD) is the unit of Currency of the United States; it has also been

St. Helens catastrophically erupted on May 18, 1980. Events 1152 - Henry II of England marries Eleanor of Aquitaine. Year 1980 ( MCMLXXX) was a Leap year starting on Tuesday (link displays the 1980 Gregorian calendar) After many months of lead-up activity, including the growth of a huge bulge on the north part of the mountain, a moderate earthquake caused the entire north flank of the mountain to slide away in the largest landslide in recorded history. ^[29] The newly-exposed hot and pressurized rock in the volcano responded by producing the largest historic volcanic eruption in the 48 contiguous U. S. states. ^[29] (See the Geology section for more detail. )

During the lead-up to the 1980 eruption of Mount St. Helens, 83-year-old Harry R. Truman, who had lived near the mountain for 54 years, became famous when he decided not to evacuate before the impending eruption, despite repeated pleas by local authorities. The 1980 eruption of Mount St Helens, a volcano located in Washington state in the United States was a major volcanic eruption. Harry Randall Truman ( October 30, 1896  &ndash May 18, 1980) came to brief fame as a resident of the U His body was never found after the eruption. Fifty-seven people were killed or never found. Had the eruption occurred one day later, when loggers would have been at work, rather than on a Sunday, the death toll would almost certainly have been much higher. ^[6]

David A. Johnston hours before he was killed by the eruption. David Alexander Johnston ( December 18, 1949 &ndash May 18, 1980) was a Volcanologist with the United States Geological

Among the victims of the 1980 eruption was 30-year-old volcanologist David A. Johnston, who was stationed on the nearby Coldwater Ridge. Volcanology (also spelled vulcanology) is the study of Volcanoes, Lava, Magma, and related geological and Geophysical phenomena David Alexander Johnston ( December 18, 1949 &ndash May 18, 1980) was a Volcanologist with the United States Geological Moments before his position was hit by the hot ash cloud, Johnston uttered his famous last words: "Vancouver! Vancouver! This is it!"^[30] Johnston's body was never found.

Mount St. Helens viewed from a regional jet, 7-24-2007

U.S. President Jimmy Carter surveyed the damage and said "Someone said this area looked like a moonscape. The President of the United States is the Head of state and Head of government of the United States and is the highest political official in United States by James Earl "Jimmy" Carter Jr (born October 1 1924 was the thirty-ninth President of the United States, serving from 1977 to 1981 and the recipient of the 2002 But the moon looks more like a golf course compared to what's up there. "^[31] A film crew, led by Seattle filmmaker Otto Seiber, was dropped by helicopter on St. History Since 400 AD Chinese children have played with bamboo flying toys. Helens on May 23 to document the destruction. Events 1430 - Siege of Compiègne: Joan of Arc is captured by the Burgundians while leading an army to relieve Compiègne Their compasses, however, spun in circles and they quickly became lost. A compass, magnetic compass or mariner's compass is a navigational instrument for determining direction relative to the earth's Magnetic poles It consists A second eruption occurred on May 25, but the crew survived and was rescued two days later by National Guard helicopter pilots. Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors. For the National Guard of a State and other countries' National Guard see National Guard. Their film, The Eruption of Mount St. Helens, later became a popular documentary.

Protection and later history

A steam plume rises from the mountain in December 2004.

In 1982, President Ronald Reagan and the U.S. Congress established the Mount St. Helens National Volcanic Monument, a 110,000 acre (445 km²) area around the mountain and within the Gifford Pinchot National Forest. The United States Congress is the bicameral Legislature of the federal government of the United States of America, consisting of two houses Mount St Helens National Volcanic Monument is a US National Monument that Gifford Pinchot ^[32]

Following the 1980 eruption, the area was left to gradually return to its natural state. In 1987, the National Forest Service reopened the mountain to climbing. It remained open until 2004 when renewed activity caused the closure of the area around the mountain (see Geology section for more detail). The 2004 and later volcanic activity of Mount St Helens has been documented as a continuous eruption with a gradual extrusion of Magma at the Mount St

Most notable was the closure of the Monitor Ridge trail, which previously let up to 100 permitted hikers per day climb to the summit. However, on July 21, 2006, the mountain was again opened to climbers. Events 356 BC - Herostratus sets fire to the Temple of Artemis in Ephesus, one of the Seven Wonders of the World Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. ^[33]

Geologic history

Ancestral stages of eruptive activity

Plate tectonics of the Cascade Range. Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere

The early eruptive stages of Mount St. Helens are known as the "Ape Canyon Stage" (around 40–35,000 years ago), the "Cougar Stage" (ca. 20–18,000 years ago), and the "Swift Creek Stage" (roughly 13–8,000 years ago). ^[34] The modern period, since about 2500 BCE, is called the "Spirit Lake Stage. " Collectively, the pre-Spirit Lake stages are known as the "ancestral stages. " The ancestral and modern stages differ primarily in the composition of the erupted lavas; ancestral lavas consisted of a characteristic mixture of dacite and andesite, while modern lava is very diverse (ranging from olivine basalt to andesite and dacite). Dacite ( deɪsaɪt) is an igneous, volcanic rock with a high iron content For the extinct cephalopod genus see Andesites. Andesite (ˈændəsaɪt is an igneous, Volcanic rock, of intermediate The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. ^[35]

St. Helens started its growth in the Pleistocene 37,600 years ago, during the Ape Canyon stage, with dacite and andesite eruptions of hot pumice and ash. The Pleistocene ('plaɪstəsin is the epoch from 18 million to 10000 years BP covering the world's recent period ^[35] 36,000 years ago a large mudflow cascaded down the volcano;^[35] mudflows were significant forces in all of St. A lahar is a type of Mudflow / Landslide composed of Pyroclastic material and Water that flows down from a Volcano, typically Helens' eruptive cycles. The Ape Canyon eruptive period ended around 35,000 years ago and was followed by 17,000 years of relative quiet. Parts of this ancestral cone were fragmented and transported by glaciers 14,000 to 18,000 years ago during the last glacial period of the current ice age. "Glacial" and "Glaciation" redirect here For the geological periods see Glacial period. An ice age is a period of long-term reduction in the Temperature of the Earth 's surface and atmosphere resulting in an expansion of continental Ice sheets ^[35]

The second eruptive period, the Cougar Stage, started 20,000 years ago and lasted for 2,000 years. ^[35] Pyroclastic flows of hot pumice and ash along with dome growth occurred during this period. A pyroclastic flow (also known as a pyroclastic density current) is a common and devastating result of some volcanic eruptions. In Volcanology, a lava dome or plug dome is a roughly circular Mound -shaped protrusion resulting from the slow eruption of Felsic Lava Another 5,000 years of dormancy followed, only to be upset by the beginning of the Swift Creek eruptive period, typified by pyroclastic flows, dome growth and blanketing of the countryside with tephra. Tephra is air-fall material produced by a volcanic eruption regardless of composition or fragment size Swift Creek ended 8,000 years ago.

Smith Creek and Pine Creek eruptive periods

A dormancy of about 4,000 years was broken around 2500 BCE with the start of the Smith Creek eruptive period, when eruptions of large amounts of ash and yellowish-brown pumice covered thousands of square miles. An eruption in 1900 BCE was the largest known eruption from St. Helens during the Holocene epoch, judged by the volume of one of the tephra layers from that period. The Holocene is a Geological epoch which began approximately 10000 years ago (about 8000 BC This eruptive period lasted until about 1600 BCE and left 18-in (46-cm) deep deposits of material 50 miles (80 km) distant in what is now Mt. Rainier National Park. Mount Rainier National Park is a United States National Park located in southeast Pierce County and northeast Lewis County in Washington Trace deposits have been found as far northeast as Banff National Park in Alberta, and as far southeast as eastern Oregon. Banff National Park (ˈbæmf is Canada's oldest national park, established in 1885 in the Canadian Rockies. Alberta (ælˈbɝtə is one of Canada's prairie provinces. It became a province on September 1 1905 Oregon ( is a state in the Pacific Northwest region of the United States. ^[36] All told there may have been up to 2. 5 cubic miles (10 km³) of material ejected in this cycle. ^[36] Some 400 years of dormancy followed.

St. Helens came alive again around 1200 BCE—the Pine Creek eruptive period. ^[36] This lasted until about 800 BCE and was characterized by smaller-volume eruptions. Numerous dense, nearly red hot pyroclastic flows sped down St. Helens' flanks and came to rest in nearby valleys. A large mudflow partly filled 40 miles (65 km) of the Lewis River valley sometime between 1000 BCE and 500 BCE.

Castle Creek and Sugar Bowl eruptive periods

The next eruptive period, the Castle Creek period, began about 400 BCE, and is characterized by a change in composition of St. Helens' lava, with the addition of olivine and basalt. The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. ^[37] The pre-1980 summit cone started to form during the Castle Creek period. Significant lava flows in addition to the previously much more common fragmented and pulverized lavas and rocks (tephra) distinguished this period. Tephra is air-fall material produced by a volcanic eruption regardless of composition or fragment size Large lava flows of andesite and basalt covered parts of the mountain, including one around the year 100 CE that traveled all the way into the Lewis and Kalama river valleys. ^[37] Others, such as Cave Basalt (known for its system of lava tubes), flowed up to 9 miles (15 km) from their vents. Lava tubes are natural conduits through which Lava travels beneath the surface of a lava flow expelled by a Volcano during an eruption ^[37] During the first century, mudflows moved 30 miles (50 km) down the Toutle and Kalama river valleys and may have reached the Columbia River. The Columbia River (known as Another 400 years of dormancy ensued. Dormancy is a period in an organism's life cycle when growth development and (in animals physical activity is temporarily suspended

The Sugar Bowl eruptive period was short and markedly different from other periods in Mount St. Helens history. It produced the only unequivocal laterally directed blast known from Mount St. Helens before the 1980 eruptions. ^[38] During Sugar Bowl time, the volcano first erupted quietly to produce a dome, then erupted violently at least twice producing a small volume of tephra, directed-blast deposits, pyroclastic flows, and lahars. ^[38]

Kalama and Goat Rocks eruptive periods

The symmetrical appearance of St. Helens prior to the 1980 eruption earned it the nickname "Mount Fuji of America". is the highest Mountain in Japan at.An Active volcano that last erupted in 1707–08 it straddles the boundary of Shizuoka and The once-familiar shape was formed out of the Kalama and Goat Rocks eruptive periods.

Roughly 700 years of dormancy were broken about 1480, when large amounts of pale gray dacite pumice and ash started to erupt, beginning the Kalama period. The eruption in 1480 was several times larger than the May 18, 1980 eruption. Events 1152 - Henry II of England marries Eleanor of Aquitaine. Year 1980 ( MCMLXXX) was a Leap year starting on Tuesday (link displays the 1980 Gregorian calendar) ^[38] In 1482, another large eruption rivaling the 1980 eruption in volume is known to have occurred. ^[38] Ash and pumice piled six miles (9. 5 km) northeast of the volcano to a thickness of three feet (1 m); 50 miles (80 km) away, the ash was two inches (5 cm) deep. Large pyroclastic flows and mudflows subsequently rushed down St. Helens' west flanks and into the Kalama River drainage system.

This 150-year period next saw the eruption of less silica-rich lava in the form of andesitic ash that formed at least eight alternating light- and dark-colored layers. The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide For the extinct cephalopod genus see Andesites. Andesite (ˈændəsaɪt is an igneous, Volcanic rock, of intermediate ^[37] Blocky andesite lava then flowed from St. Helens' summit crater down the volcano's southeast flank. ^[37] Later, pyroclastic flows raced down over the andesite lava and into the Kalama River valley. It ended with the emplacement of a dacite dome several hundred feet (~100 m) high at the volcano's summit, which filled and overtopped an explosion crater already at the summit. ^[20] Large parts of the dome's sides broke away and mantled parts of the volcano's cone with talus. Scree, also called talus and detritic cone, is a term given to broken rock that appears at the bottom of Crags mountain Cliffs or Lateral explosions excavated a notch in the southeast crater wall. St. Helens reached its greatest height and achieved its highly symmetrical form by the time the Kalama eruptive cycle ended, about 1647. ^[20] 150 years of quiet returned to the volcano.

The 57-year eruptive period that started in 1800 was named after the Goat Rocks dome, and is the first time that both oral and written records exist. ^[20] Like the Kalama period, the Goat Rocks period started with an explosion of dacite tephra, followed by an andesite lava flow, and culminated with the emplacement of a dacite dome. Dacite ( deɪsaɪt) is an igneous, volcanic rock with a high iron content Tephra is air-fall material produced by a volcanic eruption regardless of composition or fragment size The 1800 eruption probably rivalled the 1980 eruption in size, although it did not result in massive destruction of the cone. The ash drifted northeast over central and eastern Washington, northern Idaho, and western Montana. Washington ( is a state in the Pacific Northwest region of the United States. The State of Idaho ( is a state in the Pacific Northwest region of the United States of America. Montana ( is a state in the Western United States. One-third of the state in the western part contains numerous mountain ranges (approximately 77 named of the northern There were at least a dozen reported small eruptions of ash from 1831 to 1857, including a fairly large one in 1842. The vent was apparently at or near Goat Rocks on the northeast flank. ^[20] Goat Rocks dome was the site of the bulge in the 1980 eruption, and it was obliterated in the major eruption event on May 18, 1980 that destroyed the entire north face and top 1,300 feet (400 m) of the mountain. Events 1152 - Henry II of England marries Eleanor of Aquitaine. Year 1980 ( MCMLXXX) was a Leap year starting on Tuesday (link displays the 1980 Gregorian calendar)

Modern eruptive period

1980 to 2001 activity

Main article: 1980 eruption of Mount St. Helens

Mount St. The 1980 eruption of Mount St Helens, a volcano located in Washington state in the United States was a major volcanic eruption. Helens erupted on May 18, 1980, at 08:32 a. Events 1152 - Henry II of England marries Eleanor of Aquitaine. Year 1980 ( MCMLXXX) was a Leap year starting on Tuesday (link displays the 1980 Gregorian calendar) m. Pacific Daylight Time.

On March 20, 1980, Mount St. Events 1600 - The Linköping Bloodbath takes place on Maundy Thursday in Linköping, Sweden. Year 1980 ( MCMLXXX) was a Leap year starting on Tuesday (link displays the 1980 Gregorian calendar) Helens experienced a magnitude 4. The Richter magnitude scale, or more correctly local magnitude M L scale assigns a single number to quantify the amount of seismic energy released 2 earthquake. An earthquake is the result of a sudden release of energy in the Earth 's crust that creates Seismic waves Earthquakes are recorded with a Seismometer ^[1] Steam venting started on March 27. Events 196 BC - Ptolemy V ascends to the throne of Egypt. 1309 - Pope Clement V excommunicates ^[39] By the end of April, the north side of the mountain started to bulge. ^[40] With little warning, a second earthquake of magnitude 5. 1 May 18 triggered a massive collapse of the north face of the mountain. Events 1152 - Henry II of England marries Eleanor of Aquitaine. It was the largest known debris avalanche in recorded history. A landslide is a geological phenomenon which includes a wide range of ground movement such as rock falls deep failure of slopes and shallow debris flows which can occur The magma inside of St. Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet Helens burst forth into a large-scale pyroclastic flow that flattened vegetation and buildings over 230 square miles (600 km²). A pyroclastic flow (also known as a pyroclastic density current) is a common and devastating result of some volcanic eruptions. On the Volcanic Explosivity Index scale, the eruption was rated a five (a Plinian eruption). The Volcanic Explosivity Index (VEI was devised by Chris Newhall of the U Plinian eruptions are Volcanic eruptions marked by their similarity to the eruption of Mt

The collapse of the northern flank of St. Helens mixed with ice, snow, and water to create lahars (volcanic mudflows). A lahar is a type of Mudflow / Landslide composed of Pyroclastic material and Water that flows down from a Volcano, typically The lahars flowed many miles down the Toutle and Cowlitz Rivers, destroying bridges and lumber camps. A total of 3. 9 million cubic yards (3. A cubic yard is an Imperial / US customary (non- SI non- metric) unit of Volume, used in the United States, Canada and 0 million m³) of material was transported 17 miles (27 km) south into the Columbia River by the mudflows. CM3 redirects here If you were looking for the 3rd game in the Cooking Mama series abbreviated as CM3 see here. The Columbia River (known as ^[41]

For more than nine hours, a vigorous plume of ash erupted, eventually reaching 12 to 16 miles (20 to 27 km) above sea level. ^[42] The plume moved eastward at an average speed of 60 miles per hour (95 km/h), with ash reaching Idaho by noon. The State of Idaho ( is a state in the Pacific Northwest region of the United States of America.

By about 5:30 p. m. on May 18, the vertical ash column declined in stature, and less severe outbursts continued through the night and for the next several days. Events 1152 - Henry II of England marries Eleanor of Aquitaine. The St. Helens May 18 eruption released 24 megatons of thermal energy;^[43][44] it ejected more than 0. 67 cubic miles (2. 8 cubic km) of material. ^[29] The removal of the north side of the mountain reduced St. Helens' height by about 1,300 feet (400 m) and left a crater one to two miles (1. 6 to 3. 2 km) wide and 0. 5 mile (800 m) deep, with its north end open in a huge breach. The eruption killed 57 people, nearly 7,000 big game animals (deer, elk, and bear), and an estimated 12 million fish from a hatchery. A deer is a Ruminant Mammal belonging to the family Cervidae. The elk, or wapiti ( Cervus canadensis) is one of the largest Species of Deer in the world and one of the largest Mammals in ^[6] It destroyed or extensively damaged over 200 homes, 185 miles (300 km) of highway and 15 miles (24 km) of railways. * * * * * * * * * * * * * * * * * * * * * * Before adding any more images to this * * page please do carefully consider * * whether they would be mere decoration * * or actually improve "Railroad" and "Railway" both redirect here For other uses see Railroad (disambiguation. ^[6]

Lava dome growth profile from 1980–1986. In Volcanology, a lava dome or plug dome is a roughly circular Mound -shaped protrusion resulting from the slow eruption of Felsic Lava

Between 1980 and 1986, activity continued at Mount St. Helens, with a new lava dome forming in the crater. In Volcanology, a lava dome or plug dome is a roughly circular Mound -shaped protrusion resulting from the slow eruption of Felsic Lava Numerous small explosions and dome-building eruptions occurred. From December 7, 1989 to January 6, 1990, and from November 5, 1990 to February 14, 1991, the mountain erupted with sometimes huge clouds of ash. Events 43 BC - Marcus Tullius Cicero assassinated 1696 - Connecticut Route 108, one of the oldest highways Year 1989 ( MCMLXXXIX) was a Common year starting on Sunday (link displays 1989 Gregorian calendar) Events 1066 - Harold Godwinson is crowned King of England. 1205 - Philip of Swabia becomes King Year 1990 ( MCMXC) was a Common year starting on Monday (link displays the 1990 Gregorian calendar) Events 1499 - Publication of the Catholicon in Treguier ( Brittany) Year 1990 ( MCMXC) was a Common year starting on Monday (link displays the 1990 Gregorian calendar) Events 842 - Charles the Bald and Louis the German swear the Oaths of Strasbourg in the French and German Year 1991 ( MCMXCI) was a Common year starting on Tuesday (link will display full calendar of the Gregorian Calendar. ^[45]

2004 to present activity

Main article: 2004 and later volcanic activity of Mount St. Helens

Appearance of the "Whaleback" in February 2005. The 2004 and later volcanic activity of Mount St Helens has been documented as a continuous eruption with a gradual extrusion of Magma at the Mount St

Magma reached the surface of the volcano about October 11, 2004, resulting in the building of a new lava dome on the existing dome's south side. Events 1138 - A massive earthquake struck Aleppo, Syria. 1531 - Huldrych Zwingli is killed "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " This new dome continued to grow throughout 2005 and into 2006. Several transient features were observed, such as the "whaleback," which comprised long shafts of solidified magma being extruded by the pressure of magma beneath. These features are fragile and break down soon after they are formed. On July 2, 2005, the tip of the whaleback broke off, causing a rockfall that sent ash and dust several hundred meters into the air. Events 310 - Pope Miltiades is elected 626 - In fear of assassination Li Shimin ambushes and kills his rival Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. ^[46]

Mount St. Helens showed significant activity on March 8, 2005, when a 36,000-foot (11,000 m) plume of steam and ash emerged—visible from Seattle. Events 1618 - Johannes Kepler discovers the third law of planetary motion. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. ^[47] This relatively minor eruption was a release of pressure consistent with ongoing dome building. The release was accompanied by a magnitude 2. 5 earthquake.

Another feature to emerge from the dome is called the "fin" or "slab. " Approximately half the size of a football field, the large, cooled volcanic rock was being forced upward as quickly as 6 feet (2 m) per day. ^[48][49] In mid-June 2006, the slab was crumbling in frequent rockfalls, although it was still being extruded. The height of the dome was 7,550 feet (2,301 m), still below the height reached in July 2005 when the whaleback collapsed.

On October 22, 2006, at 3:13 p. Events 202 BC - Hannibal Barca, leader of the Carthaginians, is defeated by the Roman legions under Scipio Africanus Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. m. PST, a magnitude 3. 5 earthquake broke loose Spine 7. The collapse and avalanche of the lava dome sent an ash plume 2,000 feet (610 m) over the western rim of the crater; the ash plume then rapidly dissipated.

The volcano continuously steams as seen here in late 2007.

On December 19, 2006, a large white plume of condensing steam was observed, leading some media people to assume there had been a small eruption. Events 324 - Licinius abdicates his position as Roman Emperor. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. However, the Cascades Volcano Observatory of the USGS does not mention any significant ash plume. ^[50] The volcano has been in continuous eruption since October 2004, but this eruption has in large part consisted of a gradual extrusion of lava forming a dome in the crater.

On January 16, 2008, steam began seeping from a fracture atop the lava dome. Events 27 BC - The title Augustus is bestowed upon Gaius Julius Caesar Octavian by the Roman Senate. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Associated seismic activity is the most noteworthy since 2004. Scientists have suspended activities in the crater and the mountain flanks, but the risk of a major eruption is deemed low. ^[51]

See also

• Geology of the Pacific Northwest
• Cascade Volcanoes
• Silver Lake (Washington)

Notes

References

View of the hillside at the Johnston Ridge Observatory, 25 years after the eruption.

• Harris, Stephen L. (1988). "Mount St. Helens: A Living Fire Mountain", Fire Mountains of the West: The Cascade and Mono Lake Volcanoes, 1st edition, Missoula, Montana: Mountain Press Publishing Company, pp. 201–228. ISBN 0-87842-220-X.  
• Mullineaux, D. R. ; Crandell, D. R. (1981). The Eruptive History of Mount St. Helens, USGS Professional Paper 1250. Retrieved on October 28, 2006. Events 306 - Maxentius is proclaimed Roman Emperor. 312 - Battle of Milvian Bridge: Constantine Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar.
• Mullineaux, D. R. (1996). Pre-1980 Tephra-Fall Deposits Erupted From Mount St. Helens, USGS Professional Paper 1563. Retrieved on October 28, 2006. Events 306 - Maxentius is proclaimed Roman Emperor. 312 - Battle of Milvian Bridge: Constantine Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar.
• Pringle (1993). Roadside Geology of Mount St. Helens National Volcanic Monument and Vicinity, Washington State Department of Natural Resources, Division of Geology and Earth Resources Information; Circular 88.
• USGS/Cascades Volcano Observatory, Vancouver, Washington. DESCRIPTION: Mount St. Helens Volcano, Washington. Retrieved on October 28, 2006. Events 306 - Maxentius is proclaimed Roman Emperor. 312 - Battle of Milvian Bridge: Constantine Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar.

External links

• Smithsonian Institution Global Volcanism Program: Mount St. Helens
• Mount St. Helens Watch links to webcams, live video feeds and news sites to monitor Mount St. Helens
• Mount St. Helens photographs and current conditions from the United States Geological Survey website
• The VolcanoCam image of Mount St. The United States Geological Survey ( USGS) is a scientific agency of the United States government. Helens automatically updated approximately every five minutes from the U.S. Forest Service. It is located at Johnston Ridge and is able to view the new dome, even at night when the glow of new magma may be visible via the camera's infrared capabilities.
• USGS: Mount St. Helens Eruptive History
• USGS: Mount St. Helens — From the 1980 Eruption to 2000
• Most recent photos (most aerial) from the United States Geological Survey
• Enhanced night time images of Mount St Helens
• Virtual Tour of Mt St Helens. Comparison of 2003 and 2006 crater
• University of Washington Libraries: Digital Collections:
  • Mount St. Helens Post-Eruption Chemistry Database This collection contains photographs of Mount St. The United States Geological Survey ( USGS) is a scientific agency of the United States government. Helens, post-eruption, taken over the span of three years to provide a look at both the human and the scientific sides of studying the eruption of a volcano.
  • Mount St. Helens Succession Collection This collection consists of 235 photographs in a study of plant habitats following the May 18, 1980 eruption of Mount St. Helens.
• Audio recording of the May 18 1980 eruption Recorded 140 miles (225 km) southwest of the mountain. Believed to be the only audio recording of the eruption.