query: When was the last major eruption of Mount St. Helens?

title: 1980 eruption of Mount St. Helens

text: Helens has been documented as a continuous eruption with a gradual extrusion of magma at the Mount St. Helens volcano. Starting in October 2004, there was a gradual building of a new lava dome. The new dome did not rise above the caldera created by the 1980 eruption. This activity lasted until January 2008. 1980 eruption of Mount St. Helens On May 18, 1980, a major volcanic eruption occurred at Mount St. Helens, a volcano located in Skamania County, in the U.S. state of Washington. The eruption (a VEI 5 event) was the most significant volcanic eruption to occur in

title: 1980 eruption of Mount St. Helens

text: 1980 eruption of Mount St. Helens On May 18, 1980, a major volcanic eruption occurred at Mount St. Helens, a volcano located in Skamania County, in the U.S. state of Washington. The eruption (a VEI 5 event) was the most significant volcanic eruption to occur in the contiguous 48 U.S. states since the much smaller 1915 eruption of Lassen Peak in California. It has often been declared as the most disastrous volcanic eruption in U.S. history. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the

title: 1980 eruption of Mount St. Helens

text: thousands of animals were killed, and Mount St. Helens was left with a crater on its north side. At the time of the eruption, the summit of the volcano was owned by the Burlington Northern Railroad, but afterward the land passed to the United States Forest Service. The area was later preserved, as it was, in the Mount St. Helens National Volcanic Monument. Mount St. Helens remained dormant from its last period of activity in the 1840s and 1850s until March 1980. Several small earthquakes, beginning on March 15, indicated that magma may have begun moving below the volcano. On

title: Mount St. Helens

text: 1980 eruption. Mount St. Helens is west of Mount Adams, in the western part of the Cascade Range. These "sister and brother" volcanic mountains are approximately from Mount Rainier, the highest of Cascade volcanoes. Mount Hood, the nearest major volcanic peak in Oregon, is southeast of Mount St. Helens. Mount St. Helens is geologically young compared with 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. The volcano is considered the most active in the Cascades within the Holocene epoch (the last 10,000 or so

title: Mount St. Helens

text: later by National Guard helicopter pilots. Their film, "The Eruption of Mount St. Helens", later became a popular documentary. In 1982, President Ronald Reagan and the U.S. Congress established the Mount St. Helens National Volcanic Monument, a area around the mountain and within the Gifford Pinchot National Forest. Following the 1980 eruption, the area was left to gradually return to its natural state. In 1987, the U.S. 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 "Geological history" section above for more details). Most

title: 2004–08 volcanic activity of Mount St. Helens

text: 2004–08 volcanic activity of Mount St. Helens The 2004–2008 volcanic activity of Mount St. Helens, Washington, United States has been documented as a continuous eruption in the form of gradual extrusion of magma. Starting in October 2004 and ceasing in January 2008, a new lava dome was built up. The new dome did not rise above the crater created by the 1980 eruption of Mount St. Helens. On September 23, 2004, around 2:00 a.m. PDT, Mount St. Helens experienced an earthquake swarm, with about 200 small (less than magnitude 1) earthquakes occurring less than one-half mile (one kilometer) below the

title: Mount St. Helens

text: 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. 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. Roughly 700 years of dormancy were broken in 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,

title: 1980 eruption of Mount St. Helens

text: the lower Cowlitz and Columbia Rivers. The May 18, 1980, event was the most deadly and economically destructive volcanic eruption in the history of the contiguous United States. Approximately fifty-seven people were killed directly from the blast and 200 houses, 47 bridges, of railways and of highway were destroyed; two people were killed indirectly in accidents that resulted from poor visibility, and two more suffered fatal heart attacks from shoveling ash. U.S. President Jimmy Carter surveyed the damage and said it looked more desolate than a moonscape. A film crew was dropped by helicopter on Mount St. Helens on May

title: Mount St. Helens

text: 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. 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 of the mountain. On March 20, 1980, Mount St. Helens experienced a magnitude 4.2 earthquake; and, on March 27, steam venting started. By the end of April, the north side of the mountain had started to bulge. On

title: Mount St. Helens National Volcanic Monument

text: originally predicted) recovery of the land as revegetation proceeds and wildlife returns. Mount St. Helens National Volcanic Monument Mount St. Helens National Volcanic Monument is a U.S. National Monument that includes the area around Mount St. Helens in Washington. It was established on August 27, 1982 by U.S. President Ronald Reagan following the 1980 eruption. The 110,000 acre (445 km) National Volcanic Monument was set aside for research, recreation, and education. Inside the Monument, the environment is left to respond naturally to the disturbance. Mount St. Helens National Volcanic Monument was the United States' first such monument managed by the

text: Mount St. Helens National Volcanic Monument Mount St. Helens National Volcanic Monument is a U.S. National Monument that includes the area around Mount St. Helens in Washington. It was established on August 27, 1982 by U.S. President Ronald Reagan following the 1980 eruption. The 110,000 acre (445 km) National Volcanic Monument was set aside for research, recreation, and education. Inside the Monument, the environment is left to respond naturally to the disturbance. Mount St. Helens National Volcanic Monument was the United States' first such monument managed by the U.S. Forest Service. At dedication ceremonies on May 18, 1983, Max Peterson,

title: Mount St. Helens

text: Goat Rocks), and one of Kane's field sketches shows smoke emanating from about the same location. On April 17, 1857, the "Republican", a Steilacoom, Washington, newspaper, reported that "Mount St. Helens, or some other mount to the southward, is seen ... to be in a state of eruption". 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. Before the 1980 eruption, Spirit Lake offered year-round recreational activities. In the summer there was boating, swimming, and camping, while in the winter there was

title: Mount St. Helens

text: of the Pacific Ring of Fire that includes over 160 active volcanoes. This volcano is well known for its ash explosions and pyroclastic flows. Mount St. Helens is most notorious for its major 1980 eruption, the deadliest and most economically destructive volcanic event in the history of the United States. Fifty-seven people were killed; 250 homes, 47 bridges, of railways, and of highway were destroyed. A massive debris avalanche triggered by an earthquake measuring 5.1 on the Richter scale caused an eruption that reduced the elevation of the mountain's summit from to , leaving a wide horseshoe-shaped crater. The debris

title: Mount Rainier

text: twentieth century: Lassen in 1915 and St. Helens in 1980 and 2004. However, past eruptions in this volcanic arc have multiple examples of sub-plinian eruptions or higher: Crater Lake's last eruption as Mount Mazama was large enough to cause its cone to collapse, and Mt. Rainier's closest neighbor, Mount St. Helens, produced the largest eruption in the continental United States when it erupted in 1980. Statistics place the likelihood of a major eruption in the Cascade Range at 2-3 per century. Mount Rainier is currently listed as a Decade Volcano, or one of the 16 volcanoes with the greatest likelihood

text: sides of Mount St. Helens are accessible only by U.S. Forest Service roads. The main roads are: Bear Meadows is an alpine meadow and viewpoint northeast of Mt. St. Helens. It is located on U.S. Forest Service Road 99. Gary Rosenquist camped here with friends on May 17–18, 1980. He started taking his famous eruption photographs from this location. The sequence of eruption photos show give a time lapse view of the developing eruption. As the lateral blast developed, he and his friends abandoned their campsite fearing for their lives. He continued taking photos as they escaped in a car.

title: St. Helens (film)

text: St. Helens (film) St. Helens, alternatively titled St. Helens, Killer Volcano, is a 1981 made-for-cable HBO television film directed by Ernest Pintoff and starring David Huffman, Art Carney, Cassie Yates, and Albert Salmi. The film centers on the events leading up to the cataclysmic 1980 eruption of Mount St. Helens in Washington, with the story beginning on the day volcanic activity started on March 20, 1980, and ending on the day of the eruption, May 18, 1980. The film premiered on May 18, 1981, on the first anniversary of the eruption. On March 20, 1980 an earthquake of 4.1 on

title: Mount St. Helens

text: 1980, eruption. In 1482, another large eruption rivaling the 1980 eruption in volume is known to have occurred. Ash and pumice piled northeast of the volcano to a thickness of ; away, the ash was 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. Blocky andesite lava then flowed from St. Helens' summit crater down the volcano's southeast flank. Later, pyroclastic flows

title: Mount St. Helens

text: years). 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". The peak rose more than above its base, where the lower flanks merge with adjacent ridges. The mountain is across at its base, which is at an elevation of on the northeastern side and elsewhere. At the pre-eruption tree line, the width of the cone was . Streams that originate on the volcano enter three main

title: St. Helens (film)

text: few miles north of the volcano. Later that night, he pays a last visit to Harry. On the morning of May 18, 1980, David hikes to a ridge a 6 miles (10 km) north of Mount St. Helens to monitor a massive bulge that has been growing on the north face of the mountain for the past few weeks, while Harry goes fishing in Spirit Lake at the foot of the mountain. At 8:32 a.m. PDT the mountain's entire north face collapses in a massive landslide, causing the mountain to explode in a lateral eruption. The eruption kills both David

title: Lateral eruption

text: to be created by immediate decompression of a magma chamber lying not far below the flanks of a volcano. This occurred during the 1980 eruption of Mount St. Helens in the U.S. state of Washington, and also along the base or flanks of Mount Pelée's lava dome during its 1902 eruption on the northern tip of the French overseas department of Martinique in the Lesser Antilles island arc of the Caribbean. As was observed during the Mount St. Helens eruption, the rapid decompression of magma coupled with the subsidence of the mountain flank can briefly subject the surrounding landscape to

title: Saint Helens, Washington

text: of about 600 students. Saint Helens is located northwest of Mount St. Helens. The eruption of Mount St. Helens on May 18, 1980, was the deadliest and most economically destructive volcanic event in the history of the United States. Saint Helens is located at (46.3442747, -122.5287198). Saint Helens, Washington Saint Helens is an unincorporated community in Cowlitz County, Washington. Saint Helens is located east of the city of Castle Rock and along the North Fork Toutle River. Saint Helens is reached by traveling east of Castle Rock along Washington State Route 504, which is also known as the Spirit Lake

title: 1883 eruption of Krakatoa

text: the original island remained. The combination of pyroclastic flows, volcanic ash, and tsunamis associated with the Krakatoa eruptions had disastrous regional consequences. Some land in Banten, approximately 90 km south, was never repopulated; it reverted to jungle and is now the Ujung Kulon National Park. The official death toll recorded by the Dutch authorities was 36,417. Verbeek and others believe that the final major Krakatoa eruption was a lateral blast, or pyroclastic surge (similar to the catastrophic 1980 eruption of Mount St. Helens). Around noon on 27 August 1883, a rain of hot ash fell around Ketimbang (now Katibung in

title: Explosive eruption

text: Explosive eruption In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens. Such eruptions result when sufficient gas has dissolved under pressure within a viscous magma such that expelled lava violently froths into volcanic ash when pressure is suddenly lowered at the vent. Sometimes a lava plug will block the conduit to the summit, and when this occurs, eruptions are more violent. Explosive eruptions can send rocks, dust, gas and pyroclastic material up to 20 km into the atmosphere at a rate of up to

title: Phreatic eruption

text: Phreatic eruption A phreatic eruption, also called a phreatic explosion, ultravulcanian eruption or steam-blast eruption, occurs when magma heats ground or surface water. The extreme temperature of the magma (anywhere from ) causes near-instantaneous evaporation to steam, resulting in an explosion of steam, water, ash, rock, and volcanic bombs. At Mount St. Helens, hundreds of steam explosions preceded a 1980 plinian eruption of the volcano. A less intense geothermal event may result in a mud volcano. Phreatic eruptions typically include steam and rock fragments; the inclusion of liquid lava is unusual. The temperature of the fragments can range from cold

title: 1980 eruption of Mount St. Helens

text: on [the official] List". According to Melanson's brother, in October 1983, Cowlitz County officials told his family that Melanson "is believed [...] a victim of the May 18, 1980, eruption" and that after years of searching, the family eventually decided "he's buried in the ash". Taking these two points of dispute into consideration, the direct death toll could be as low as fifty-five or as high as sixty. When combined with the four indirect victims mentioned earlier, those numbers range from fifty-nine to sixty-four. The ash fall created some temporary major problems with transportation, sewage disposal, and water treatment systems.

title: Mount Cayley volcanic field

text: large volcanic eruption from any volcanoes in the Mount Cayley field would have major effects on the Sea-to-Sky Highway and municipalities such as Squamish, Whistler, Pemberton and probably Vancouver. Because of these concerns, the Geological Survey of Canada is planning to create hazard maps and emergency plans for Mount Cayley, as well as for the Mount Meager massif north of the volcanic field, which experienced a major volcanic eruption 2,350 years ago similar to the 1980 eruption of Mount St. Helens. Like many other volcanoes in the Garibaldi Volcanic Belt, Mount Cayley has been the source for several large landslides.

title: 1980 eruption of Mount St. Helens

text: produced an additional five explosive eruptions between May and October 1980. Through early 1990 at least 21 periods of eruptive activity had occurred. The volcano remains active, with smaller, dome-building eruptions continuing into 2008. An eruption occurred on May 25, 1980, at 2:30 a.m. that sent an ash column into the atmosphere. The eruption was preceded by a sudden increase in earthquake activity and occurred during a rainstorm. Erratic wind from the storm carried ash from the eruption to the south and west, lightly dusting large parts of western Washington and Oregon. Pyroclastic flows exited the northern breach and covered

text: head of the USFS, said, "we can take pride in having preserved the unique episode of natural history for future generations." Since then, many trails, viewpoints, information stations, campgrounds, and picnic areas have been established to accommodate the increasing number of visitors each year. Beginning in 1983, visitors have been able to drive to Windy Ridge, only northeast of the crater. Mountain climbing to the summit of the volcano has been allowed since 1986. The Mount St. Helens Visitor Center at Silver Lake, about west of Mount St. Helens and five miles (8 km) east of Interstate 5 (outside the

title: Mount Shasta

text: Shasta is still alive. The worst-case scenario for an eruption is a large pyroclastic flow, such as what occurred in the 1980 eruption of Mount St. Helens. Since there is ice, such as Whitney Glacier and Mud Creek Glacier, lahars would also result. Ash would probably blow inland, perhaps as far as eastern Nevada. There is a small chance an eruption could result in a collapse of the mountain, as happened when Mount Mazama in Oregon collapsed to form what is now called Crater Lake, but this is of much lower probability. The United States Geological Survey monitors Mount Shasta

title: Mount Pinatubo

text: also irreparably damaged the Philippine Air Force's recently retired fleet of Vought F-8s, as these were in open storage at Basa Air Base at the time. The June 15 eruption had a volcanic explosivity index (VEI) of 6, and came some 450–500 years after the volcano's last known eruptive activity. The eruption ejected about of material, making it the largest eruption since that of Novarupta in 1912 and some ten times larger than the 1980 eruption of Mount St. Helens. Ejected material such as tephra fallout and pyroclastic flow deposits are much less dense than magma, and the volume of

title: Causes of landslides

text: same time as an eruption, but occasionally they may be triggered by other factors such as a seismic shock or heavy rainfall. They are particularly common on strato volcanoes, which can be massively destructive due to their large size. The most famous debris avalanche occurred at Mount St Helens during the massive eruption in 1980. On May 18, 1980, at 8:32 a.m. local time, a magnitude 5.1 earthquake shook Mount St. Helens. The bulge and surrounding area slid away in a gigantic rockslide and debris avalanche, releasing pressure, and triggering a major pumice and ash eruption of the volcano. The

title: Volcanology of New Zealand

text: Waikato to the Tasman Sea. New Zealand's largest lake, Lake Taupo, fills the caldera formed in this eruption. Taupo's most recent major eruption, the Taupo or Hatepe eruption, took place around 180 CE, and is New Zealand's largest eruption since Oruanui. It ejected some 120 km³ of material (rating 7 on the VEI scale), with around 30 km³ ejected in just a few minutes. It is believed that the eruption column was high, twice as high as the eruption column from Mount St. Helens in 1980. This makes it one of the most violent eruptions in the last 5000 years

title: Mount St. Helens

text: damaged over 200 homes, of highway and of railways. Between 1980 and 1986, activity continued at Mount St. Helens, with a new lava dome forming in the crater. 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. 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. This new dome continued to grow throughout 2005 and into 2006. Several transient

title: Geology of the Pacific Northwest

text: in the Cascadia subduction zone. Volcanoes of the Garibaldi Volcanic Belt have been sporadically active over a time span of several millions of years. The northernmost member, the Mount Meager massif, was responsible for a major catastrophic eruption that occurred about 2,350 years ago. This eruption may have been close in size to that of the 1980 eruption of Mount St. Helens. Ash from this eruption can be traced eastward to western Alberta. It is also the most unstable volcanic massive in Canada, which has dumped clay and rock several meters deep into the Pemberton Valley at least three times

title: Mount Rainier

text: of causing great loss of life and property if eruptive activity resumes. If Mt. Rainier were to erupt as powerfully as Mount St. Helens did in its May 18, 1980 eruption, the effect would be cumulatively greater, because of the far more massive amounts of glacial ice locked on the volcano compared to Mount St. Helens, the vastly more heavily populated areas surrounding Rainier, and the simple fact that Mt Rainier is a much bigger volcano, almost twice the size of St. Helens. Lahars from Rainier pose the most risk to life and property, as many communities lie atop older

title: Mount St. Helens

text: the mountain run through Cowlitz County to the west and Lewis County to the north. State Route 504, locally known as the Spirit Lake Memorial Highway, connects with Interstate 5 at Exit 49, to the west of the mountain. That 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 to the southwest. The community nearest the volcano is Cougar, Washington, in the Lewis River valley south-southwest of the peak. Gifford Pinchot National Forest surrounds Mount St. Helens. During the winter of 1980–1981,

title: 1980 eruption of Mount St. Helens

text: small, red-hot pyroclastic flows. A third dome began to form within 30 minutes after the final explosion on October 18, and within a few days, it was about wide and high. In spite of the dome growth next to it, a new glacier formed rapidly inside the crater. All of the post-1980 eruptions were quiet dome-building events, beginning with the December 27, 1980, to January 3, 1981, episode. By 1987 the third dome had grown to be more than wide and high. Further eruptions occurred over a few months between 1989 and 1991. The 2004–08 volcanic activity of Mount St.

title: Cascade Volcanoes

text: 1915 eruption of remote Lassen Peak in Northern California, the arc was quiet for more than a century. Then, on May 18, 1980, the dramatic eruption of little-known Mount St. Helens shattered the quiet and brought the world's attention to the arc. Geologists were also concerned that the St. Helens eruption was a sign that long-dormant Cascade volcanoes might become active once more, as in the period from 1800 to 1857 when a total of eight erupted. None have erupted since St. Helens, but precautions are being taken nevertheless, such as the Mount Rainier Volcano Lahar Warning System in Pierce

title: Mount St. Helens

text: 1200 BCE — the Pine Creek eruptive period. 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 of the Lewis River valley sometime between 1000 BCE and 500 BCE. 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 pre-1980 summit cone started to form during the Castle Creek period. Significant

title: 1980 eruption of Mount St. Helens

text: nearly crippling blow to tourism, an important industry in Washington. Not only was tourism down in the Mount St. Helens–Gifford Pinchot National Forest area, but conventions, meetings and social gatherings also were cancelled or postponed at cities and resorts elsewhere in Washington and neighboring Oregon not affected by the eruption. The adverse effect on tourism and conventioneering, however, proved only temporary. Mount St. Helens, perhaps because of its reawakening, has regained its appeal for tourists. The United States Forest Service and the State of Washington opened visitor centers and provided access for people to view the volcano's devastation. St. Helens

title: 1980 eruption of Mount St. Helens

text: intangible costs of the eruption. Unemployment in the immediate region of Mount St. Helens rose tenfold in the weeks immediately following the eruption, and then returned to near-normal levels once timber-salvaging and ash-cleanup operations were underway. Only a small percentage of residents left the region because of lost jobs owing to the eruption. Several months after May 18, a few residents reported suffering stress and emotional problems, even though they had coped successfully during the crisis. Counties in the region requested funding for mental health programs to assist such people. Initial public reaction to the May 18 eruption dealt a

title: 1980 eruption of Mount St. Helens

text: 23 to document the destruction. However, their compasses spun in circles and they quickly became lost. A second eruption occurred the next day (see below), but the crew survived and were rescued two days after that. The eruption ejected more than of material. A quarter of that volume was fresh lava in the form of ash, pumice and volcanic bombs while the rest was fragmented, older rock. The removal of the north side of the mountain (13% of the cone's volume) reduced Mount St. Helens' height by about and left a crater wide and deep with its north end open

title: 1980 eruption of Mount St. Helens

text: is equivalent to about of solid rock, or about 7% of the amount of material that slid off in the debris avalanche. By around 5:30 p.m. on May 18, the vertical ash column declined in stature, but less severe outbursts continued through the next Generally, given that the way airborne ash is deposited after an eruption is strongly influenced by the meteorological conditions, a certain variation of the ash type will occur, as a function of distance to the volcano or time elapsed from eruption. The ash from Mount St. Helens is no exception, and hence the ash properties have

title: Mount St. Helens

text: dome. Associated seismic activity was the most noteworthy since 2004. Scientists suspended activities in the crater and the mountain flanks, but the risk of a major eruption was deemed low. By the end of January, the eruption paused; no more lava was being extruded from the lava dome. On July 10, 2008, it was determined that the eruption had ended, after more than six months of no volcanic activity. American Indian lore contains numerous legends to explain the eruptions of Mount St. Helens and other Cascade volcanoes. The most famous of these is the Bridge of the Gods legend told

title: 1980 eruption of Mount St. Helens

text: groundwater system, causing many steam-driven explosions (phreatic eruptions). As May 18 dawned, Mount St. Helens' activity did not show any change from the pattern of the preceding month. The rate of bulge movement, sulfur dioxide emission, and ground temperature readings did not reveal any changes indicating a catastrophic eruption. USGS volcanologist David A. Johnston was on duty at an observation post approximately north of the volcano: as of 6 a.m., Johnston's measurements did not indicate any unusual activity. Suddenly, at 8:32 a.m., a magnitude 5.1 earthquake centered directly below the north slope triggered that part of the volcano to slide,

title: Mount St. Helens

text: recorded sighting of Mount St. Helens on May 19, 1792, while surveying the northern Pacific Ocean coast. Vancouver named the mountain for British diplomat Alleyne Fitzherbert, 1st Baron St Helens on October 20, 1792, as it came into view when the "Discovery" passed into the mouth of the Columbia River. 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). Alarmed by the "dry snow," the Nespelem tribe of

title: Mount St. Helens

text: also to rename each major Cascade mountain after a former President of the United States. In his scheme Mount St. Helens was to be renamed Mount Washington. The first authenticated eyewitness report of a volcanic eruption was made in March 1835 by Meredith Gairdner, while working for the Hudson's Bay Company stationed at Fort Vancouver. 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.

text: by a small tremor that lasted nearly ninety minutes, and a magnitude 2.7 earthquake. But by the end of January, the lava dome growth had stopped. On July 10, 2008, it was determined that the eruption that began in 2004 had ended, after 6 months of inactivity. 2004–08 volcanic activity of Mount St. Helens The 2004–2008 volcanic activity of Mount St. Helens, Washington, United States has been documented as a continuous eruption in the form of gradual extrusion of magma. Starting in October 2004 and ceasing in January 2008, a new lava dome was built up. The new dome did

title: Mount St. Helens

text: northeastern Washington danced and prayed rather than collecting food and suffered during that winter from starvation. 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. 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. In 1829 Hall J. Kelley led a campaign to rename the Cascade Range as the President's Range and

title: Mount St. Helens

text: Another member of the expedition later described "cellular basaltic lavas" at the mountain's base. 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. The eruptions of this period were likely phreatic (steam explosions). Josiah Parrish in Champoeg, Oregon witnessed Mount St. Helens in eruption on November 22, 1842. Ash from this eruption may have reached The Dalles, Oregon, 48 miles (80 km) southeast of the volcano. In October 1843, future California governor Peter H. Burnett recounted a story

title: Mount St. Helens

text: features were observed, such as a lava spine nicknamed the "whaleback", which comprised long shafts of solidified magma being extruded by the pressure of magma beneath. These features were fragile and broke down soon after they were 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. Mount St. Helens showed significant activity on March 8, 2005, when a plume of steam and ash emerged—visible from Seattle. This relatively minor eruption was a release of pressure consistent with ongoing dome building. The release was

title: 1980 eruption of Mount St. Helens

text: of ash fell. Continuing St. Helens' ash fell in the western part of Yellowstone National Park by 10:15 p.m. and was seen on the ground in Denver, Colorado, the next day. In time, ash fall from this eruption was reported as far away as Minnesota and Oklahoma, and some of the ash drifted around the globe within about During the nine hours of vigorous eruptive activity, about 540,000,000 tons () of ash fell over an area of more than . The total volume of the ash before its compaction by rainfall was about . The volume of the uncompacted ash

title: 1980 eruption of Mount St. Helens

text: was new lava, and the rest was fragmented, older rock. The huge ensuing ash cloud sent skyward from St. Helens' northern foot was visible throughout the quiet zone. The near-supersonic lateral blast, loaded with volcanic debris, caused devastation as far as from the volcano. The area affected by the blast can be subdivided into three roughly concentric zones: By the time this pyroclastic flow hit its first human victims, it was still as hot as and filled with suffocating gas and flying debris. Most of the 57 people known to have died in that day's eruption succumbed to asphyxiation while

title: 1980 eruption of Mount St. Helens

text: sheared off at the stump seconds earlier by the blast of super-heated volcanic gas and ash that had immediately followed and overtook the initial landslide. The debris was transported along with the water as it returned to its basin, raising the surface level of Spirit Lake by about 200 feet. More than three decades after the eruption, floating log mats persist on Spirit Lake and nearby St. Helens Lake, changing position with the wind. The rest of the trees, especially those that were not completely detached from their roots, were turned upright by their own weight and became waterlogged, sinking

title: Mount St. Helens

text: May 18, a second earthquake, of magnitude 5.1, triggered a massive collapse of the north face of the mountain. It was the largest known debris avalanche in recorded history. The magma in St. Helens burst forth into a large-scale pyroclastic flow that flattened vegetation and buildings over . More than 1.5 million metric tons of sulfur dioxide was released into the atmosphere. On the Volcanic Explosivity Index scale, the eruption was rated a five, and categorized as a Plinian eruption. The collapse of the northern flank of St. Helens mixed with ice, snow, and water to create lahars (volcanic mudflows).

title: 1980 eruption of Mount St. Helens

text: light is absorbed by the substance. It is known that the silicate particles have a real index of refraction ranging between 1.5 and 1.6 for visible light. However, there is a spectrum of colors associated with samples of volcanic ash, from very light to dark gray. This makes for variations in the measured imaginary refractive index under visible light. In the case of Mount St. Helens, the ash settled in three main layers on the ground: For example, when comparing the imaginary part of the refractive index "k" of stratospheric ash from 15 km and 18 km from the volcano

title: Mount St. Helens

text: 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. This eruptive period lasted until about 1600 BCE and left deep deposits of material distant in what is now Mt. Rainier National Park. Trace deposits have been found as far northeast as Banff National Park in Alberta, and as far southeast as eastern Oregon. All told there may have been up to of material ejected in this cycle. Some 400 years of dormancy followed. St. Helens came alive again around

title: Mount St. Helens

text: Mount St. Helens Mount St. Helens or Louwala-Clough (known as Lawetlat'la to the indigenous Cowlitz people, and Loowit to the Klickitat) is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is northeast of Portland, Oregon and south of Seattle, Washington. 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. The volcano is located in the Cascade Range and is part of the Cascade Volcanic Arc, a segment

title: Mount St. Helens

text: route can be accessed via the Marble Mountain Sno-Park and the Swift Ski Trail. Mount St. Helens Mount St. Helens or Louwala-Clough (known as Lawetlat'la to the indigenous Cowlitz people, and Loowit to the Klickitat) is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is northeast of Portland, Oregon and south of Seattle, Washington. 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. The volcano is located

title: Mount St. Helens

text: May 18, the vertical ash column declined in stature, and less severe outbursts continued through the night and for the next several days. The St. Helens May 18 eruption released 24 megatons of thermal energy; it ejected more than of material. The removal of the north side of the mountain reduced St. Helens' height by about and left a crater to wide and 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. It destroyed or extensively

title: The Eruption of Mount Pelee

text: "The Eruption of Mount Pelee" was presumed lost for many years; a film in the collection of the Cinémathèque Française was sometimes misidentified as Méliès's film, but it was in fact Zecca's version. Méliès's film was finally recovered in 2007, when a copy was found and restored by the Filmoteca de Catalunya. The Eruption of Mount Pelee Éruption volcanique à la Martinique, released in the United States as The Eruption of Mount Pelee and in Britain as The Terrible Eruption of Mount Pelée and Destruction of St. Pierre, Martinique, is a 1902 French short silent film directed by Georges Méliès.

title: 1980 eruption of Mount St. Helens

text: Lewis River to accommodate possible mudflows and flood waters. In total Mount St. Helens released 24 megatons of thermal energy, 7 of which were a direct result of the blast. This is equivalent to 1,600 times the size of the atomic bomb dropped on Hiroshima. There is a minor controversy in regard to the exact death toll. The figure most commonly cited is fifty-seven. However, there are two points of dispute. The first point regards two officially listed victims, Paul Hiatt and Dale Thayer. They were reported missing after the explosion. In the aftermath, investigators were able to locate individuals

title: Mount St. Helens

text: the pyroclastic flow, Johnston radioed his famous last words: "Vancouver! Vancouver! This is it!" Johnston's body was never found. U.S. President Jimmy Carter surveyed the damage and said, "Someone said this area looked like a moonscape. But the moon looks more like a golf course compared to what's up there." A film crew, led by Seattle filmmaker Otto Seiber, was dropped by helicopter on St. Helens on May 23 to document the destruction. Their compasses, however, spun in circles and they quickly became lost. A second eruption occurred on May 25, but the crew survived and was rescued two days

title: Mount St. Helens

text: avalanche was up to in volume. The Mount St. Helens National Volcanic Monument was created to preserve the volcano and allow for the eruption's aftermath to be scientifically studied. 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. The mountain includes layers of basalt and andesite through which several domes of dacite lava have erupted. 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

title: 1980 eruption of Mount St. Helens

text: harmonic tremors were first detected on April 1, alarming geologists and prompting Governor Dixy Lee Ray to declare a state of emergency on April 3. Governor Ray issued an executive order on April 30 creating a "red zone" around the volcano; anyone caught in this zone without a pass faced a $500 fine or six months in jail. This precluded many cabin owners from visiting their property. By April 7, the combined crater was and deep. A USGS team determined in the last week of April that a section of St. Helens' north face was displaced outward by at least

title: 1888 eruption of Mount Bandai

text: 1888 eruption of Mount Bandai The 1888 eruption of Mount Bandai was a major volcanic eruption which occurred during the Meiji period of the Empire of Japan. The eruption occurred on July 15, 1888, and pyroclastic flows buried villages on the northern foot of the mountain, and devastated the eastern part of Bandai region, Fukushima Prefecture north of Tokyo. At least 477 people were killed and hundreds more were injured and rendered homeless in what became the worst volcanic disaster in recent Japanese history. Mount Bandai is a stratovolcano. Its last eruption had occurred in 806. Mount Bandai had a

title: 1888 eruption of Mount Bandai

text: especially the multi-hued lakes of Goshiki-numa. (caldera) 1888 eruption of Mount Bandai The 1888 eruption of Mount Bandai was a major volcanic eruption which occurred during the Meiji period of the Empire of Japan. The eruption occurred on July 15, 1888, and pyroclastic flows buried villages on the northern foot of the mountain, and devastated the eastern part of Bandai region, Fukushima Prefecture north of Tokyo. At least 477 people were killed and hundreds more were injured and rendered homeless in what became the worst volcanic disaster in recent Japanese history. Mount Bandai is a stratovolcano. Its last eruption had

title: Mount St. Helens

text: Mount St. Helens is a popular climbing destination for both beginning and experienced mountaineers. The peak is climbed year-round, although it is more often climbed from late spring through early fall. All routes include sections of steep, rugged terrain. A permit system has been in place for climbers since 1987. A climbing permit is required year-round for anyone who will be above on the slopes of Mount St. Helens. The standard hiking/mountaineering route in the warmer months is the Monitor Ridge Route, which starts at the Climbers Bivouac. This is the most popular and crowded route to the summit in

text: large, cooled volcanic rock was being forced upward as quickly as 6 feet (2 m) per day, though the top part of the slab would usually collapse on a daily basis, under its own weight. On July 21, 2006, the rim was reopened to hikers. On December 19, 2006, an eruption sent a steam plume billowing over Washington. After a relatively quiet 2007, on January 16, 2008, USGS geologist John S. Pallister spotted steam seeping from the lava dome in Mount St. Helens' crater. At approximately the same time, the Pacific Northwest Seismograph Network recorded a magnitude 2.9 earthquake, followed

text: saying "We no longer think that an eruption is imminent in the sense of minutes or hours." Magma reached the surface of the volcano around October 11, resulting in the building of a new lava dome on the existing dome's south side. Dome building continued, with the USGS reporting in early November 2004 that magma was being extruded at a rate of 7 to 10 cubic meters per second. Had magma continued to extrude at this rate uninterrupted, the crater would have been completely filled and Mount St. Helens would have regained its former height in about eleven years. The

title: The Eruption of Mount Pelee

text: The Eruption of Mount Pelee Éruption volcanique à la Martinique, released in the United States as The Eruption of Mount Pelee and in Britain as The Terrible Eruption of Mount Pelée and Destruction of St. Pierre, Martinique, is a 1902 French short silent film directed by Georges Méliès. The film is a short reconstruction, using miniature models, of a recent historical event: the eruption on 8 May 1902 of Mount Pelée, which destroyed the town of Saint-Pierre, Martinique. Mount Pelée looms over the town of Saint-Pierre. Fire and smoke rises from the crater; then lava begins pouring down the sides

title: Windy Ridge (Mount St. Helens)

text: Windy Ridge (Mount St. Helens) Windy Ridge is a ridge and eponymous Forest Highway in the Mount St. Helens National Volcanic Monument. The ridge goes between Windy Pass and Independence Pass, east of Spirit Lake. Several road guides list Windy Ridge Road (NF-99) as one of the best roads in Washington State due to its good pavement, good views, and winding "sweeper" curves enjoyable to many drivers and motorcycle riders. At the end of the road at elevation, at above Spirit Lake, there is a viewpoint into the St. Helens crater. NF-99 meets Forest Road 25 near Wakepish Sno-park running

title: Mount St. Helens

text: of the gods 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 mountain is also of sacred importance to the Cowlitz and Yakama tribes that also historically lived in the area. They find the area above

title: Windy Ridge (Mount St. Helens)

text: to Windy Ridge and other Spirit Lake overlooks past places such as Bear Meadow Viewpoint, Miner's Car, Meta Lake and Cascade Peaks. This is one of the most popular back-country destinations on the Forest and Monument. Windy Ridge (Mount St. Helens) Windy Ridge is a ridge and eponymous Forest Highway in the Mount St. Helens National Volcanic Monument. The ridge goes between Windy Pass and Independence Pass, east of Spirit Lake. Several road guides list Windy Ridge Road (NF-99) as one of the best roads in Washington State due to its good pavement, good views, and winding "sweeper" curves enjoyable

text: contained about 50 million cubic yards (40 million cubic meters) of material. The total amount of glacier lost by this date was estimated to be 5–10%, but the flow of water from the crater was almost unchanged because the porous nature of the floor of the crater caused the water to be absorbed quickly. Mount St. Helens experienced major activity again on March 8, 2005 at about 5:30 P.M. PST, when a 36,000-foot (11 km) plume of steam and presumably ash was witnessed emerging from the volcano, accompanied by a tremor that measured about magnitude 2.5. The plume was visible

title: 1980 eruption of Mount St. Helens

text: it has been discovered that they have similar values around 700 nm (around 0.009), while they differ significantly around 300 nm. Here, the 18 km ("k" was found to be around 0.009) sample was much more absorbent than the 15 km sample ("k" was found to be around 0.002). The hot, exploding material also broke apart and melted nearly all of the mountain's glaciers along with most of the overlying snow. As in many previous St. Helens' eruptions, this created huge lahars (volcanic mudflows) and muddy floods that affected three of the four stream drainage systems on the mountain, and

title: 1980 eruption of Mount St. Helens

text: Rosenquist, his party and his photographs survived because the blast was deflected by local topography short of his location. Most of St. Helens' former north side became a rubble deposit long, averaging thick; the slide was thickest at below Spirit Lake and thinnest at its western margin. The landslide temporarily displaced the waters of Spirit lake to the ridge north of the lake, in a giant wave approximately high. This in turn created a avalanche of debris consisting of the returning waters and thousands of uprooted trees and stumps. Some of these remained intact with roots, but most had been

title: Mount St. Helens

text: andesite and dacite). 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. Thirty-six thousand years ago a large mudflow cascaded down the volcano; mudflows were significant forces in all of St. 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. The second eruptive period,

title: St. Helens (film)

text: wrote that, "Dave's life was too meritorious to require fictional embellishments," and that, "Dave was a superbly conscientious and creative scientist." Don Swanson, a USGS geologist who was Johnston's friend and who, due to other commitments, had convinced Johnston to take his place at the Coldwater II observation post on the day of the eruption, believed that a movie based on Johnston's true life and exploits would have been a hit because of his friend's character. St. Helens (film) St. Helens, alternatively titled St. Helens, Killer Volcano, is a 1981 made-for-cable HBO television film directed by Ernest Pintoff and starring

title: 1980 eruption of Mount St. Helens

text: into the muddy sediments at the bottom where they have become petrified in the anaerobic and mineral-rich waters. This provides insight into other sites with a similar fossil record. The landslide exposed the dacite magma in St. Helens' neck to much lower pressure, causing the gas-charged, partially molten rock and high-pressure steam above it to explode a few seconds after the landslide started. Explosions burst through the trailing part of the landslide, blasting rock debris northward. The resulting blast laterally directed the pyroclastic flow of very hot volcanic gases, ash and pumice formed from new lava, while the pulverized old

title: 1980 eruption of Mount St. Helens

text: the avalanche and initial pyroclastic flow were still advancing, a huge ash column grew to a height of above the expanding crater in less than 10 minutes and spread tephra into the stratosphere for 10 straight hours. Near the volcano, the swirling ash particles in the atmosphere generated lightning, which in turn started many forest fires. During this time, parts of the mushroom-shaped ash-cloud column collapsed, and fell back upon the earth. This fallout, mixed with magma, mud, and steam, sent additional pyroclastic flows speeding down St. Helens' flanks. Later, slower flows came directly from the new north-facing crater and

title: Mount St. Helens

text: the summer and gains about in approximately to reach the crater rim. Although strenuous, it is considered non-technical climb that involves some scrambling. Most climbers complete the round trip in 7 to 12 hours. The Worm Flows Route is considered the standard winter route on Mount St. Helens, as it is the most direct route to the summit. The route gains about in elevation over about from trailhead to summit but does not demand the technical climbing that some other Cascade peaks like Mount Rainier do. The route name refers to the rocky lava flows that surround the route. This

title: St. Helens, Oregon

text: Helens has one sister city: St. Helens, Oregon St. Helens is the county seat of Columbia County, Oregon. It was founded by Captain Henry Montgomery Knighton, a native of New England, in 1845, as "Plymouth". The name was changed to St. Helens in the latter part of 1850 for its view of Mount St. Helens, roughly away in Washington. The city is about 28 miles (45 km) northwest of Portland. Its population was 12,883 at the 2010 census. St. Helens was established as a river port on the Columbia River in the 1840s. In 1853, the Pacific Mail Steamship Company

title: St. Helens, Oregon

text: St. Helens, Oregon St. Helens is the county seat of Columbia County, Oregon. It was founded by Captain Henry Montgomery Knighton, a native of New England, in 1845, as "Plymouth". The name was changed to St. Helens in the latter part of 1850 for its view of Mount St. Helens, roughly away in Washington. The city is about 28 miles (45 km) northwest of Portland. Its population was 12,883 at the 2010 census. St. Helens was established as a river port on the Columbia River in the 1840s. In 1853, the Pacific Mail Steamship Company tried to make the city

title: St Helens, Merseyside

text: Western. The Liverpool to Manchester line serves the St Helens area at Rainhill, Lea Green and St Helens Junction before passing on to Earlestown and Newton-le-Willows. The St Helens Junction and Rainhill buildings are two of the original stations built when the line opened in 1830 and are both now Listed Buildings. Collins Green railway station closed in 1951 and the old Lea Green station in 1955. Until the 1950s three lines ran through St Helens: and A major redevelopment of St Helens Central was completed in 2007 at a cost of £6.2 million. which the Council hopes will encourage

title: History of St Helens, Merseyside

text: still beneath the surface. The last colliery in the modern metropolitan borough and in the St Helens area of the South Lancashire Coalfield, was Parkside, in Newton-le-Willows, which was closed in 1992. A section dedicated to the changing political structure of St Helens between 1700 and 1974 There are 159 listed buildings and 12 scheduled monuments in the Metropolitan Borough of St Helens. History of St Helens, Merseyside St Helens () is a large town and the administrative seat of the Metropolitan Borough of St Helens in Merseyside, England. The town was incorporated as a municipal borough in 1868, responsible

title: Mount St. Helens

text: 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. The streams are fed by abundant rain and snow. The average annual rainfall is , and the snow pack on the mountain's upper slopes can reach . The Lewis River is impounded by three dams for hydroelectric power generation. 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. Although Mount St. Helens is in Skamania County, Washington, access routes to

title: 1980 eruption of Mount St. Helens

text: activity and gas emission steadily increased in early August, and on August 7 at 4:26 p.m., an ash cloud slowly expanded into the sky. Small pyroclastic flows came through the northern breach and a weaker outpouring of ash rose from the crater. This continued until 10:32 p.m. when a second large blast sent ash high into the air, proceeding due north. A second dacite dome filled this vent a few days later. Two months of repose were ended by an eruption lasting from October 16 to 18. This event obliterated the second dome, sent ash in the air and created

title: Mount St. Helens

text: in the contiguous United States. The early eruptive stages of Mount St. Helens are known as the "Ape Canyon Stage" (around 40,000–35,000 years ago), the "Cougar Stage" (ca. 20,000–18,000 years ago), and the "Swift Creek Stage" (roughly 13,000–8,000 years ago). 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

title: The Chronicle (St. Helens)

text: The Chronicle (St. Helens) The Chronicle is a weekly newspaper published in St. Helens, Oregon, United States. It was established in 1881 and is owned by Country Media. "The Chronicle" is published on Wednesdays and has a circulation of 4,372. It is the newspaper of record for Columbia County. When the newspaper started in 1881, it was named the "Oregon Mist", later renamed to the "St. Helens Mist". In 1933, the "Mist" bought out the "St. Helens Sentinel", which was established in 1926, and the paper was renamed the "Sentinel-Mist". In 1936, a paper named the "St. Helens Chronicle" was

title: Baron St Helens

text: the United Kingdom, allowing him to sit in the House of Lords.On his death in 1839, both baronies became extinct. Lord St Helens was the son of William Fitzherbert, Member of Parliament for Derby, and a younger brother of Sir William Fitzherbert, 1st Baronet. The third creation came on 31 December 1964 when the Conservative politician Michael Hughes-Young was made Baron St Helens, of St Helens in the County Palatine of Lancaster. He had earlier represented Wandsworth Central in the House of Commons. It was one of the last hereditary baronies ever created in the Peerage of the United Kingdom.

title: Explosive eruption

text: the cone, usually the crater. However, in the case of the eruption of Mount St. Helens, pressure was released on the side of the volcano, rather than the crater. The sudden release of pressure causes the gases in the magma to suddenly froth and create volcanic ash and pumice, which is then ejected through the volcanic vent to create the signature eruption column commonly associated with explosive eruptions. The size and duration of the column depends on the volume of magma being released and how much pressure the magma was under. Pyroclastic flows occur towards the end of an explosive

title: St Helens, Merseyside

text: and filled. An extensive tram and trolleybus system was operated between 1880 and 1936 trolleybuses commenced in 1927 and ceased 30 June 1958 when the last Prescot Circle trolleybus was replaced by a bus service. From 1919, the service was operated by the St Helens Corporation Tramways, prior to this it had been operated by the St. Helens and District Tramways Company, and subsequently the New St Helens and District Tramways Company. Originally horse drawn, they became steam powered by 1890, and then electric by 1899. The original lines were all removed during the war for steel for the war

text: Mount St. Helens VolcanoCam located at Johnston Ridge was able to view the new dome especially at night when the glow of new magma was visible via the camera's infrared capabilities. Included in the new dome was a feature dubbed the "whaleback" (named such because of its close resemblance to the back of a whale), which was a long shaft of solidified magma being extruded by pressure of magma underneath it. This feature was very hot but fragile. The edges of it began crumbling rapidly, forming loose material around the new dome. The rate of crumbling soon matched the rate

title: St Helens, Tasmania

text: for seabirds and waders. 35 km to the west is Mount Victoria Forest Reserve near the high St Columba Falls. St Helens has a mild temperate climate, with four distinct seasons. Summers are warm and sunny and winters are cool to mild. Rain falls consistently through the year, peaking slightly in winter. Being on the East Coast, St Helens winter temperatures are warmer than most parts of Tasmania. Summer temperatures are not as warm as inland areas, however are still warmer than experienced in Hobart. St Helens record high temperature is recorded on 30 January 2009, the equal second highest

title: Mount St. Helens

text: skiing. Fifty-seven people were killed during the eruption. Had the eruption occurred one day later, when loggers would have been at work, rather than on a Sunday, the death toll could have been much higher. 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. His body was never found after the eruption. Another victim of the eruption was 30-year-old volcanologist David A. Johnston, who was stationed on the nearby Coldwater Ridge. Moments before his position was hit by

title: Hatepe eruption

text: Hatepe eruption The Hatepe eruption, named for the Hatepe Plinian pumice tephra layer, sometimes referred to as the Taupo eruption and dated to around 180 AD, was Lake Taupo's most recent major eruption. It is considered New Zealand's largest eruption during the last 20,000 years. The eruption ejected some , a VEI 7 eruption, of which was ejected in a few minutes. This makes it one of the most violent eruptions in the last 5000 years, comparable to the Minoan eruption in the 2nd millennium BC, the 946 eruption of Paektu Mountain and the 1815 eruption of Mount Tambora. The

title: Hōei eruption of Mount Fuji

text: Hōei eruption of Mount Fuji The started on 16 December 1707 (23rd day of the 11th month of the year Hōei 4) and ended about 1 January 1708 (9th day of the 12th month of the year Hōei 4) during the Edo period. Today the crater of the main eruption can be visited from the Fujinomiya or Gotemba Trails on Mount Fuji. Hokusai's "One Hundred Views of Mount Fuji" includes an image of the small crater at a secondary eruption site on the southwestern slope. This was called "Mount Hōei", because the eruption occurred in the fourth year of Hōei.

title: Baron St Helens

text: Baron St Helens Baron St Helens is a title that has been created three times, once in the Peerage of Ireland and twice in the Peerage of the United Kingdom. The first two creations were both in favour of the same person, but are now extinct. The first creation came in the Peerage of Ireland in 1791 when the Chief Secretary for Ireland Alleyne Fitzherbert was made Baron St Helens. In 1801 he was further honoured when he was made Baron St Helens, of St Helens on the Isle of Wight in the County of Southampton, in the Peerage of

title: 1815 eruption of Mount Tambora

text: 1815 eruption of Mount Tambora The 1815 eruption of Mount Tambora was one of the most powerful in recorded history, with a Volcanic Explosivity Index (VEI) of 7. It is the most recently known VEI-7 event and the only unambiguously confirmed VEI-7 eruption since the Lake Taupo eruption in about 180 CE. Mount Tambora is on the island of Sumbawa in present-day Indonesia, then part of the Dutch East Indies. Although its eruption reached a violent climax on 10 April 1815, increased steaming and small phreatic eruptions occurred during the next six months to three years. The ash from the