1980 eruption of Mount St. Helens

Major volcanic eruption in Skamania County, Washington Eruption of Mount St. Helens other eruptions Mount St. Helens#Geology May 2025 January 2023 Eruption of Mount St. Helens MSH80 eruption mount st helens 05-18-80-dramatic-edit.jpg The eruption column, May 18, 1980 1980 05 18 (climactic episode) 321050 Eruptions St. Helens 2021-04-27 Mount St. Helens Phreatic Plinian Peléan Skamania County, Washington, U.S. 46 12 1 N 122 11 12 W type:mountain_region:US-WA inline,title 5 File:St helens map showing 1980 eruption deposits.png Map of eruption deposits Approximately 57 deaths, about $1.1 billion in property damage ($US-GDP 1.1 1980 1 c billion in US-GDP); caused a collapse of the volcano's northern flank, deposited ash in eleven U.S. states and five Canadian provinces On May18, 1980, at 8:32a.m., Mount St. Helens in Skamania County, Washington, United States, experienced a catastrophic explosive eruption which had a volcanic explosivity index of5. It was the first to occur in the contiguous United States since the much smaller 1915 eruption of Lassen Peak in California.Fisher Heiken Hulen 1998 294 The main eruption was preceded by a series of volcanic explosions, pyroclastic flows, and phreatic blasts beginning in March 1980. It has often been considered the most disastrous volcanic event in U.S. history. The eruption was preceded by a series of earthquakes and steam-venting episodes caused by an injection of magma at shallow depth below the volcano that created a large bulge and a fracture system on the mountain's north slope. An earthquake at 8:32:11am PDT (UTC−7) on May 18, 1980,USGS M 5.7 Mt. St Helens earthquake trigger https://earthquake.usgs.gov/earthquakes/eventpage/uw10084803/executive earthquake.usgs.gov May 18, 2020 caused the entire weakened north face to slide away, a sector collapse which was the largest subaerial landslide in recorded history.What was the largest landslide in the United States? In the world? https://www.usgs.gov/faqs/what-was-largest-landslide-united-states-world?qt-news_science_products=0#qt-news_science_products January 25, 2021 www.usgs.gov This allowed the partly molten rock, rich in high-pressure gas and steam, to suddenly explode northward toward Spirit Lake in a hot mix of lava and pulverized rock, overtaking the landslide. An eruption column rose 80,000 ft km mi 0 into the atmosphere and deposited ash in 11 U.S. states and various Canadian provinces.https://edmontonjournal.com/news/local-news/u-of-a-researchers-looking-for-albertans-who-experienced-volcano U of A researchers looking for Albertans who experienced volcano Short Dylan March 19, 2019 edmontonjournal.com Edmonton Journal May 1, 2019 dust was found most heavily in the foothills area in southern Alberta, but may have drifted as far north as Red Deer. At the same time, snow, ice, and several entire glaciers on the volcano melted, forming a series of large lahars (volcanic mudslides) that reached as far as the Columbia River, nearly 50 mi km to the southwest. Less severe outbursts continued into the next day, only to be followed by other large, but not as destructive, eruptions later that year. The thermal energy released during the eruption was equal to 26 megatons of TNT.https://giph.io/v.php?pm=3ZJG Mount Saint Helens Eruption - giph.io giph.io September 25, 2017 https://web.archive.org/web/20170926041703/https://giph.io/v.php?pm=3ZJG September 26, 2017 dead mdy-all About 57 people were killed, including innkeeper and World War I veteran Harry R. Truman, photographers Reid Blackburn and Robert Landsburg, and volcanologist David A. Johnston.http://www.kgw.com/news/pdf/helens_deathlist.pdf https://web.archive.org/web/20090326085504/http://www.kgw.com/news/pdf/helens_deathlist.pdf March 26, 2009 dead KGW news Those who lost their lives because of the May 18, 1980 eruption of Mount St. Helens Hundreds of square miles were reduced to wasteland, causing over $1billion in damage (equivalent to $US-GDP 1.1 1980 1 billion in US-GDP). 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 the United States Forest Service acquired the land from the railroad after the eruption.Tilling, Robert I. Topinka, Lyn Swanson, Donald A. 1990 https://vulcan.wr.usgs.gov/Volcanoes/MSH/Publications/MSHPPF/MSH_past_present_future.html Eruptions of Mount St. Helens: Past, Present, and Future U.S. Geological Survey (Special Interest Publication) December 5, 2010 dead https://web.archive.org/web/20111026174423/http://vulcan.wr.usgs.gov/Volcanoes/MSH/Publications/MSHPPF/MSH_past_present_future.html "Ironically, in 1980 the section of land containing the summit crater was owned by the Burlington Northern Railroad; it has since been acquired by USFS by land exchanges." October 26, 2011 mdy-all (adapted public domain text).Runte Alfred Al Runte 1983 Burlington Northern and the Legacy of Mount St. Helens https://www.jstor.org/stable/40490550 The Pacific Northwest Quarterly 74 3 116–123 40490550 0030-8803 Burlington Northern, as co-owner of Mount St. Helens with the federal government, was especially concerned about the future of the peak, [...] Extending from the lip of the crater down the slopes opposite the blast area, arcing 90 degrees from due south to due west, lay the remainder of the square mile that originally had formed part of the [Northern Pacific Railroad's 1864] land grant. Clearly, this portion of the mountain had no commercial use but great value as the nucleus of the national park or monument already proposed by environmental groups. In recognition of the popularity of these proposals, Burlington Northern in 1982 restored the area to the federal government. The area was later preserved in the Mount St. Helens National Volcanic Monument and the State of Washington recognized the month of May as "Volcano Awareness Month". Events are held at Mt. St. Helens and within the region to discuss the eruption and safety concerns, and to commemorate lives lost during the disaster.Barker Cade Volcano Awareness Month: Numerous activities available in person, social media https://www.thereflector.com/stories/volcano-awareness-month-numerous-activities-available-in-person-social-media,340241 May 21, 2024 The Reflector (Battle Ground, Washington) May 13, 2024 October 18, 2025 https://web.archive.org/web/20251018130542/https://thereflector.com/stories/volcano-awareness-month-numerous-activities-available-in-person-social-media,340241 dead Build-up to the eruption thumb|alt=Erupting conical volcano|USGS photo showing a pre-avalanche eruption on April 10 Mount St. Helens remained dormant from its last period of activity in the 1840s and 1850s until March 1980.The Volcano: Full Theater, Stuck Curtain; Hall Packed for Volcano, But the Curtain Is Stuck The Washington Post March 31, 1980 Gorney Cynthia Several small earthquakes, beginning on March 15, indicated that magma might have begun moving below the volcano. On March 20, at 3:45pm Pacific Standard Time, a shallow 4.2-magnitudeearthquake, centered below the volcano's north flank, signaled the volcano's return from 123years of hibernation.Harris 1988 202 A gradually building earthquake swarm saturated area seismographs and started to climax at about noon on March 25, reaching peak levels in the next two days, including an earthquake registering 5.1 on the Richter scale among a total of 174 shocks of magnitude2.6 or greater.Oregon volcano may be warming up for an eruption Christian Science Monitor March 27, 1980 Ray Dewey https://www.csmonitor.com/1980/0327/032754.html October 31, 2010 dead https://web.archive.org/web/20120629144823/http://www.csmonitor.com/1980/0327/032754.html June 29, 2012https://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/32228/32228.html Mount St. Helens Precursory Activity: March 22–28, 1980 https://web.archive.org/web/20121005165544/http://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/32228/32228.html October 5, 2012 June 6, 2015 United States Geological Survey 2001 Shocks of magnitude 3.2 or greater occurred at a slightly increasing rate during April and May, with five earthquakes of magnitude4 or above per day in early April, and eight per day the week before May 18.Harris 1988 202 Initially, no direct sign of eruption was seen, but small earthquake-induced avalanches of snow and ice were reported from aerial observations. thumb|left|alt=Open crater as seen from the rim.|Mount St. Helens seen from Monitor Ridge. This image shows the cone of devastation, the huge crater open to the north, the post eruption lava dome inside, and Crater Glacier surrounding the lava dome. The small photo on the left was taken from Spirit Lake before the eruption, and the small photo on the right was taken after the eruption from roughly the same place. Spirit Lake can also be seen in the larger image, as well as Mount Rainier and Mount Adams. At 12:36 pm on March 27, phreatic eruptions (explosions of steam caused by magma suddenly heating groundwater) ejected and smashed rock from within the old summit crater, excavating a new crater 250 ft 5 wide,Harris 1988 202https://news.google.com/newspapers?id=CLdeAAAAIBAJ&pg=4395%2C10406076 Lewiston Morning Tribune Associated Press Mount St. Helens blows its top March 28, 1980 1Ahttps://news.google.com/newspapers?id=yvtLAAAAIBAJ&pg=6950%2C6305315 The Spokesman-Review Rose Robert L. Washington volcano blowing its top March 28, 1980 1https://news.google.com/newspapers?id=CldOAAAAIBAJ&pg=4005%2C3414023 Spokane Daily Chronicle Associated Press Blumenthal Les Hot volcanic ash moves lower March 29, 1980 1 and sending an ash column about 7000 ft km into the air. By this date, a 16,000 ft km mid -long eastward-trending fracture system had also developed across the summit area.Harris 1988 204 This was followed by more earthquake swarms and a series of steam explosions that sent ash 10000 to 11000 ft above their vent.Harris 1988 202 Most of this ash fell between 3 and 12 mi 0 on from its vent, but some was carried 150 mi on south to Bend, Oregon, or 285 mi 5 on east to Spokane, Washington.Harris 1988 203 A second, new crater and a blue flame were observed on March 29.Harris 1988 203https://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/32944/32944.html 2001 Mount St. Helens Precursory Activity: March 29 – April 4, 1980 https://web.archive.org/web/20121010215612/http://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/32944/32944.html October 10, 2012 June 6, 2015 United States Geological Survey The flame was visibly emitted from both craters and was probably created by burning gases. Static electricity generated from ash clouds rolling down the volcano sent out lightning bolts that were up to 2 mi km 0 on long.Harris 1988 203 Ninety-three separate outbursts were reported on March 30,Harris 1988 203 and increasingly strong 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 (US 500 1980 -2 eq) or six months in jail.https://news.google.com/newspapers?id=_FVOAAAAIBAJ&pg=7192%2C48656 The Spokesman-Review Hazard zones created around mountain Associated Press May 1, 1980 8https://news.google.com/newspapers?id=0dIvAAAAIBAJ&pg=7138%2C400221 Spokane Daily Chronicle UPI Volcano bulge grows May 2, 1980 6 This precluded many cabin owners from visiting their property.https://news.google.com/newspapers?id=MdMvAAAAIBAJ&pg=3464%2C394099 Spokane Daily Chronicle wire services May 17, 1980 1 Mount St. Helens cabin owners angry at ban thumb|alt=Side of the mountain|Photo showing the bulge growing due to a cryptodome on April 27 By April 7 the combined crater was 1700 by 1200 ft on and 500 ft on deep.https://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/45411/45411.html 2001 Mount St. Helens Precursory Activity: April 5–11, 1980 https://web.archive.org/web/20121011064804/http://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/45411/45411.html October 11, 2012 June 6, 2015 United States Geological Survey A USGS (United States Geological Survey) team determined in the last week of April that a 1.5 mi km mid -diameter on section of St. Helens' north face was displaced outward by at least 270 ft m 0 on.Harris 1988 204 For the rest of April and early May, this bulge grew by 5 to 6 ft on per day, and by mid-May, it extended more than 400 ft -1 on north.Harris 1988 204 As the bulge moved northward, the summit area behind it progressively sank, forming a complex, down-dropped block called a graben. Geologists announced on April 30 that sliding of the bulge area was the greatest immediate danger and that such a landslide might spark an eruption. https://news.google.com/newspapers?id=E6xfAAAAIBAJ&pg=4181%2C10255394 Lewiston Morning Tribune Associated Press St. Helens: Huge hunk of mountain could still hit lake April 29, 1980 3B These changes in the volcano's shape were related to the overall deformation that increased the volume of the volcano by 0.03 mi3 km3 on by mid-May.https://pubs.usgs.gov/gip/msh//reawakening.html 1997 Reawakening and Initial Activity May 31, 2007 United States Geological Survey https://web.archive.org/web/20070609062743/http://pubs.usgs.gov/gip/msh/reawakening.html June 9, 2007 live This volume increase presumably corresponded to the volume of magma that pushed into the volcano and deformed its surface. Because the intruding magma remained below ground and was not directly visible, it was called a cryptodome, in contrast to a true lava dome exposed at the surface. Volcanologist Barry Voight was contacted by Rocky Crandell,Thompson, p. 76. a USGS employee working in the Vancouver office near the mountain.Thompson, p. 31. Crandell sought Voight's expertise in landslides, hoping Voight would opine on the growing bulge.Harris, p. 204.Olson, p. 71. In his reporting to Crandell and his associates, Voight, who observed the mountain April 11–19, said that the bulge could fail and collapse the volcano's entire north sector. He suggested they begin monitoring the rate of movement of the bulge, worried that the collapse could trigger an eruption. He also advised hiring a local surveyor to take measurements, offending several of the geologists.Thompson, p. 77. Shortly after, Voight left the mountain and returned to teaching classes at Pennsylvania State University. On May 1, he sent his full report to the USGS, summarizing his predictions, predicting the failure of the bulge and the collapse of the mountain's north side followed by a violent eruption that would require an extensive evacuation zone.Thompson, p. 97.Olson, p. 72. On May 7, eruptions similar to those in March and April resumed, and over the following days, the bulge approached its maximum size. All activity had been confined to the 350-year-old summit dome and did not involve any new magma. About 10,000 earthquakes were recorded before the May 18 event, with most concentrated in a small zone less than 1.6 mi on directly below the bulge. Visible eruptions ceased on May 16, reducing public interest and consequently the number of spectators in the area. https://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/510517/510517.html 2001 Mount St. Helens Precursory Activity: May 10–17, 1980 https://web.archive.org/web/20100312113040/http://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/510517/510517.html March 12, 2010 June 6, 2015 United States Geological Survey dead Mounting public pressure then forced officials to allow 50 carloads of property owners to enter the danger zone on Saturday, May 17, to gather whatever property they could carry. https://news.google.com/newspapers?id=q_hVAAAAIBAJ&pg=6779%2C5349904 Eugene Register-Guard Associated Press Homes near volcano checked May 18, 1980 6A Another trip was scheduled for 10am the next day, a Sunday, when more than three hundred loggers who would normally be working in the area were not present. By the time of the climactic eruption, dacite magma intruding into the volcano had forced the north flank outward nearly 500 ft on and heated the volcano's groundwater system, causing many steam-driven explosions (phreatic eruptions). Landslide and climactic phase thumb|upright=1.5|alt=Computer simulation with photos of erupting ash|Sequence of events on May 18 thumb|Lakes nearest to Mount St. Helens have been partly covered with fallen trees since the eruption. This photograph was taken in 2012. thumb|alt=Hummocky terrain|The North Fork Toutle River valley filled with landslide deposits At dawn May 18, Mount St. Helens' activity did not show any change from the pattern of the preceding month. The rates of bulge movement and 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 around 6 mi km 0 on north of the volcano. At 6:00am Johnston's measurements did not indicate any unusual activity. At 8:32 am, a magnitude 5.1 earthquake centered directly below the north slope triggered that part of the volcano to slide,Harris 1988 205 approximately 7–20seconds after the shock, followed a few seconds later by the main volcanic blast. The sector collapse, the largest subaerial landslide in recorded history, traveled at 110 to 155 mph km/h m/s -1 on and moved across Spirit Lake's west arm. Part of it hit a 1,150 ft m mid -high on ridge about 6 mi km 0 on north. Some of the slide spilled over the ridge, but most of it moved 13 mi km 0 on down the North Fork Toutle River, filling its valley up to 600 ft m deep with avalanche debris.Harris 1988 205 An area of about 24 mi2 km2 on was covered, and the total volume of the deposit was about 0.7 mi3 km3 on. Scientists were able to reconstruct the motion of the landslide from a series of rapid photographs by Gary Rosenquist, who was camping 11 mi km on away from the blast 46 18 49 N 122 02 12 W region:US-WA_type:event. Rosenquist, his party, and his photographs survived because the blast was deflected by local topography 1 mi km 1 on short of his location.Fisher Heiken Hulen 1998 117 Eruption of Mount St. Helens, heard from 140 miles away (filtered and amplified).wav Sound of the eruption of Mount St. Helens, as heard from 140 miles away Amateur recording of a series of booms produced by the eruption, as heard from the town of Newport, Oregon (audio filtered and amplified). WAV Most of St. Helens' former north side became a rubble deposit 17 mi km on long, averaging 150 ft m on thick; the slide was thickest at 1 mi km on 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 about 600 ft m on high.Harris 1988 209 This, in turn, created a 295 ft m on on 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 sheared off at the stump seconds earlier by the blast of superheated volcanic gas and ash that had immediately followed and overtaken 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 ft on. Four 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 into the muddy sediments at the bottom where they are in the process of becoming petrified in the anaerobic and mineral-rich waters. This provides insight into other sites with a similar fossil record.Fritz William J. Harrison Sylvia 1985 Transported trees from the 1982 Mount St. Helens sediment flows: Their use as paleocurrent indicators Sedimentary Geology scientific 42 1,2 49–64 10.1016/0037-0738(85)90073-9 1985SedG...42...49F Pyroclastic flows Initial lateral blast thumb|Computer graphics showing the May 18 landslide (green) being overtaken by the initial pyroclastic flow (red) The landslide exposed the dacite magma in Mount 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 directed the pyroclastic flow laterally. It consisted of very hot volcanic gases, ash, and pumice formed from new lava, as well as pulverized old rock, which hugged the ground. Initially moving about 220 mph km/h on, the blast quickly accelerated to around 670 mph km/h on, and it may have briefly passed the speed of sound.Harris 1988 205 Pyroclastic flow material passed over the moving avalanche and spread outward, devastating a fan-shaped area 23 miles across by 19 miles long (37kmby 31km).Harris 1988 205 In total, about 230 sqmi on of forest were knocked down,Harris 1988 205 and extreme heat killed trees miles beyond the blow-down zone. At its vent, the lateral blast probably did not last longer than about thirty seconds, but the northward-radiating and expanding blast cloud continued for about another minute. Superheated flow material flashed water in Spirit Lake and North Fork Toutle River to steam, creating a larger, secondary explosion that was heard as far away as British Columbia,Harris 1988 206 Montana, Idaho, and Northern California, yet many areas closer to the eruption (Portland, Oregon, for example) did not hear the blast. This so-called "quiet zone" extended radially a few tens of miles from the volcano and was created by the complex response of the eruption's sound waves to differences in temperature and air motion of the atmospheric layers, and to a lesser extent, local topography. Later studies indicated that one-third of the 0.045 mi3 on of material in the flow was new lava, and the rest was fragmented, older rock.Harris 1988 206 Lateral blast result thumb|alt=Heavily damaged car embedded in gray soil|Reid Blackburn's car after the eruption thumb|Many trees in the direct blast zone were snapped off at their bases and the earth was stripped and scorched. 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 19 mi km on from the volcano. The area affected by the blast can be subdivided into roughly concentric zones: Direct blast zone, the innermost zone, averaged about 8 mi km on in radius, an area in which virtually everything, natural or artificial, was obliterated or carried away. For this reason, this zone also has been called the "tree-removal zone". The flow of the material carried by the blast was not deflected by topographic features in this zone. The blast released energy equal to 24 MtTNT PJ in off. Channelized blast zone, an intermediate zone, extended out to distances as far as 19 mi km on from the volcano, an area in which the flow flattened everything in its path and was channeled to some extent by topography. In this zone, the forces and direction of the blast are strikingly demonstrated by the parallel alignment of toppled large trees, broken off at the base of the trunk as if they were blades of grass mown by a scythe. This zone was also known as the "tree-down zone". Channeling and deflection of the blast caused strikingly varied local effects that still remained conspicuous after some decades. Where the blast struck open land directly, it scoured it, breaking trees off short and stripping vegetation and even topsoil, thereby delaying revegetation for many years. Where the blast was deflected so as to pass overhead by several metres, it left the topsoil and the seeds it contained, permitting faster revegetation with scrub and herbaceous plants, and later with saplings. Trees in the path of such higher-level blasts were broken off wholesale at various heights, whereas nearby stands in more sheltered positions recovered comparatively rapidly without conspicuous long-term harm. Seared zone, also called the "standing dead" zone, the outermost fringe of the impacted area, is a zone in which trees remained standing, but were singed brown by the hot gases of the blast. thumb|upright|Volcanologist David A. Johnston (pictured 13 hours before his death) was among the approximately 57 people killed by the eruption. thumb|alt=Satellite image of the area surrounding Mount St. Helens, labeled with various locations. The primary locations marked are: Mount St. Helens (in the center of the volcano there is a circular black crater); and to the north of the volcano the Coldwater II observation post, where Johnston was camped. The other locations marked are three lakes (Spirit Lake, Bear Cove, and Coldwater lake) and a river (North Fork Toutle River).|Johnston's Coldwater II observation post, marked by the red dot, was in the path of the blast when the north side of Mount St. Helens collapsed. By the time this pyroclastic flow hit its first human victims, it was still as hot as 360 C F flip and filled with suffocating gas and flying debris.Harris 1988 206 Most of the 57 people known to have died in that day's eruption succumbed to asphyxiation, while several died from burns. Lodge owner Harry R. Truman was buried under hundreds of feet of avalanche material 46 15 59.6 N 122 09 33.3 W region:US-WA_type:event. Volcanologist David A. Johnston, who was stationed at observation post Coldwater II 46 16 37.5 N 122 13 28.0 W region:US-WA_type:event, located just six miles (ten km) north of the mountain, was killed 46 17 37 N 122 13 27.1 W region:US-WA_type:event, as was Reid Blackburn 46 17 53.1 N 122 17 23.5 W region:US-WA_type:event, a Vancouver Columbian and National Geographic photographer who was situated near Coldwater Creek 46 17 55.8 N 122 17 22.9 W region:US-WA_type:event, 8 mi km 0 us from the volcano, on the day of the eruption.Robinson, Erik (April 1, 2010). "Volcano's toll hits close to home". The Colombian. Retrieved May 20, 2011. Robert Landsburg, another photographer, who was within a few miles of the summit 46 12 46.3 N 122 16 03.3 W region:US-WA_type:event, was killed by the ash cloud. He was able to protect his film with his body, and the surviving photos provided geologists with valuable documentation of the historic eruption.Robert Coenraads (2006). "Natural Disasters and How We Cope", p.50. Millennium House, 978-1-921209-11-6. Another eruption victim, amateur radio operator Gerry Martin, located near the Coldwater peak and farther north of Johnston's position 46 17 59.7 N 122 12 55 W region:US-WA_type:event, reported his sighting of the eruption enveloping the ColdwaterII observation post. As the blast overwhelmed Johnston's post, Martin declared solemnly: "Gentlemen, the camper and car that's sitting over to the south of me is covered. It's going to hit me, too." before his radio went silent.Stepankowsky, Andre http://www.helenair.com/news/state-and-regional/article_314586af-d2be-5df2-a55d-4cfb5e370b8f.html Memories, lessons from mountain's fury The Daily News May 16, 2005 April 4, 20102016-09-07 Gerry Martin https://eruptionbook.com/book/gerry-martin/ 2022-05-18 Eruption: The Untold Story of Mount St. Helens en-US September 26, 2022 https://web.archive.org/web/20220926041307/https://eruptionbook.com/book/gerry-martin/ dead Later flows Subsequent outpourings of pyroclastic material from the breach left by the landslide consisted mainly of new magmatic debris rather than fragments of pre-existing volcanic rocks. The resulting deposits formed a fan-like pattern of overlapping sheets, tongues, and lobes. At least 17 separate pyroclastic flows occurred during the May 18 eruption, and their aggregate volume was about 0.05 mi3 km3 on. The flow deposits were still at about 300 to 420 C F -1 flip two weeks after they erupted. Secondary steam-blast eruptions fed by this heat created pits on the northern margin of the pyroclastic-flow deposits, at the south shore of Spirit Lake, and along the upper part of the North Fork Toutle River. These steam-blast explosions continued sporadically for weeks or months after the emplacement of pyroclastic flows, and at least one occurred a year later, on May 16, 1981. Ash column thumb|The ash cloud produced by the eruption, as seen from the village of Toledo, Washington, 35 mi km on to the northwest of Mount St. Helens. The cloud was roughly 40 mi km on wide and 15 mi km ft on high. thumb|alt=Satellite photo|Ash cloud from Mt. St. Helens as captured by the GOES 3 weather satellite at 15:45 UTC As the avalanche and initial pyroclastic flow were still advancing, a huge ash column grew to a height of 12 mi km on above the expanding crater in less than ten minutes and spread tephra into the stratosphere for ten straight hours.Harris 1988 206 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 consisted of glowing pumice bombs and very hot pumiceous ash. Some of these hot flows covered ice or water, which flashed to steam, creating craters up to 65 ft on in diameter and sending ash as much as 6500 ft on into the air.Harris 1988 208 Strong, high-altitude wind carried much of this material east-northeasterly from the volcano at an average speed around 60 mph -1. By 9:45am, it had reached Yakima, Washington, 90 mi on away, and by 11:45 it was over Spokane, Washington. A total of 4 to 5 in mm on of ash fell on Yakima, and areas as far east as Spokane were plunged into darkness by noon, where visibility was reduced to 10 ft 0 on and 0.5 in mm on of ash fell.Harris 1988 206 Continuing eastward, https://news.google.com/newspapers?id=rfhVAAAAIBAJ&pg=6619%2C6085698 Eugene Register-Guard Associated Press Cloud of ash soaring over Kentucky May 20, 1980 5A St. Helens' ash fell in the western part of Yellowstone National Park by 10:15pm, and was seen on the ground in Denver the next day.Harris 1988 206 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 two weeks.https://www.usgs.gov/faqs/how-far-did-ash-mount-st-helens-travel How far did the ash from Mount St. Helens travel? USGS February 22, 2018 During the nine hours of vigorous eruptive activity, about 540,000,000 tons (540 e6ST e6MT or on) of ash fell over an area of more than 22000 mi2 km2 on. The total volume of the ash before its compaction by rainfall was about 0.3 mi3 km3 on. The volume of the uncompacted ash is equivalent to about 0.05 mi3 km3 on of solid rock, or about 7% of the amount of material that slid off in the debris avalanche. By 5:30pm on May 18, the vertical ash column declined in stature, but less severe outbursts continued through the next several days.Harris 1988 210 Ash properties thumb|Residual lateral blast effects in the channelized blast zone, thirty years after the eruption 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, hence the ash properties have large variations. Taylor H. E. Lichte F. E. Chemical composition of Mount St. Helens volcanic ash Geophysical Research Letters 1980 7 949–952 11 10.1029/GL007i011p00949 1980GeoRL...7..949T free Chemical composition The bulk chemical composition of the ash has been found to be about 65% silicon dioxide, 18% aluminum oxide, 5% ferric oxide, 4% each calcium oxide and sodium oxide, and 2% magnesium oxide. Trace elements were also detected, their concentrations varying as 0.05–0.09% chlorine, 0.02–0.03% fluorine, and 0.09–0.3% sulfur. Index of refraction The index of refraction, a measure used in physics to describe how light propagates through a particular substance, is an important property of volcanic ash. This number is complex, having both real and imaginary parts, the real part indicating how light disperses and the imaginary part indicating how light is absorbed by the substance. The silicate particles are known to have a real index of refraction ranging between 1.5 and 1.6 for visible light. However, a spectrum of colors is 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. Patterson E. M. Measurement of the Imaginary Part of the Refractive Index Between 300 and 700 Nanometers for Mount St. Helens Ash Science 1981 211 836–838 4484 10.1126/science.211.4484.836 17740398 1981Sci...211..836P In the case of Mount St. Helens, the ash settled in three main layers on the ground: The bottom layer was dark gray and was found to be abundant in older rocks and crystal fragments. The middle layer consisted of a mixture of glass shards and pumice. The top layer was ash consisting of very fine particles. For example, when comparing the imaginary part of the refractive index k of stratospheric ash from 15 and 18 km flip on from the volcano, they have similar values around 700nm (around 0.009), while they differ significantly around 300nm. Here, the 18 km flip 1 sample (k was found to be around 0.009) was much more absorbent than the 15 km flip sample (k was found to be around 0.002). Mudslides flow downstream thumb|alt=Trees covered in muddy ash|Mudline next to Muddy River from the 1980 lahars 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,Harris 1988 208 and which started to move as early as 8:50am.Harris 1988 209 Lahars travelled as fast as 90 mph km/h on while still high on the volcano, but progressively slowed to about 3 mph km/h on on the flatter and wider parts of rivers. Mudflows from the southern and eastern flanks had the consistency of wet concrete as they raced down Muddy River, Pine Creek, and Smith Creek to their confluence at the Lewis River. Bridges were taken out at the mouth of Pine Creek and the head of Swift Reservoir, which rose 2.6 ft m onHarris 1988 208 by noon to accommodate the nearly 18000000 yd3 m3 on of additional water, mud, and debris. Glacier and snowmelt mixed with tephra on the volcano's northeast slope to create much larger lahars. These mudflows traveled down the north and south forks of the Toutle River and joined at the confluence of the Toutle forks and the Cowlitz River near Castle Rock, Washington, at 1:00pm. Ninety minutes after the eruption, the first mudflow had moved 27 mi km 0 on upstream, where observers at Weyerhaeuser's Camp Baker saw a 12 ft m mid -high 0 on wall of muddy water and debris pass.Harris 1988 209 Near the confluence of the Toutle's north and south forks at Silver Lake, a record flood stage of 23.5 ft m 1 on was recorded.Harris 1988 209 A large but slower-moving mudflow with a mortar-like consistency was mobilized in early afternoon at the head of the Toutle River north fork. By 2:30pm the massive mudflow had destroyed Camp Baker,Harris 1988 209 and in the following hours, seven bridges were carried away. Part of the flow backed up for 2.5 mi km 1 on soon after entering the Cowlitz River, but most continued downstream. After traveling 17 mi km on further, an estimated 3,900,000 yd3 m3 on of material were injected into the Columbia River, reducing the river's depth by 25 ft m 0 on for a 4 mi km 0 on on stretch.Harris 1988 209 The resulting 13 ft m on on river depth temporarily closed the busy channel to ocean-going freighters, costing Portland, Oregon, an estimated $5 million (equivalent to $US-GDP 5 1980 1 million US-GDP).Harris 1988 210 Ultimately, more than 65 e6yd3 e6m3 e9ft3 on of sediment were dumped along the lower Cowlitz and Columbia Rivers. Aftermath thumb|Mount St. Helens as seen on May 17, 1980 one day before the eruption, photographed from the Johnston ridge thumb|Mount St. Helens in September 1980 approximately four months after the eruption, photographed from roughly the same location as the earlier picture. Note the barrenness of the terrain as compared to the image above. Direct results The May 18, 1980, event was the most deadly and economically destructive volcanic eruption in the history of the contiguous United States. About 57 people were killed directly from the blast, and 200 houses, 47 bridges, 15 mi km on of railways, and 185 mi km on 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. https://volcano.oregonstate.edu/faq/what-were-effects-people-when-mt-st-helens-erupted What were the effects on people when Mt St Helens erupted? May 13, 2010 Oregon State University November 7, 2015 U.S. President Jimmy Carter surveyed the damage, and said it looked more desolate than a moonscape.Patty Murray Patty Murray http://frwebgate.access.gpo.gov/cgi-bin/getpage.cgi?dbname=2005_record&page=S5252&position=all 25th Anniversary of the Mount St. Helens Eruption U.S. Government Printing Office May 17, 2005 May 18, 2009 Congressional Record – Senate S5252 Egan Timothy Trees Return to St. Helens, But Do They Make a Forest? 1 The New York Times June 26, 1988 https://www.nytimes.com/1988/06/26/us/trees-return-to-st-helens-but-do-they-make-a-forest.html May 18, 2009 A film crew was dropped by helicopter on Mount St. Helens on May 23 to document the destruction, but they quickly became lost, which the crew attributed to “magnetism in the ash and our contour maps made meaningless on the altered slopes”.Michael Lienau http://www.globalnetproductions.com/mshsurvival.html https://web.archive.org/web/20110711101500/http://www.globalnetproductions.com/mshsurvival.html July 11, 2011 To Touch a Volcano: A Filmmaker's Story of Survival Global Net Productions May 19, 2009 dead A second eruption occurred the next day (see below), but the crew survived and were rescued two days after that.Muhlstein Julie 2020-05-17 Mount St. Helens 'changed my life,' says Camano filmmaker https://www.heraldnet.com/news/mount-st-helens-changed-my-life-says-camano-filmmaker/ 2022-11-08 HeraldNet.com en-US The eruption ejected more than 1 mi3 km3 on of material.Harris 1988 211 A quarter of that volume was fresh lava in the form of ash, pumice, and volcanic bombs, while the rest was fragmented, older rock.Harris 1988 211 The removal of the north side of the mountain (13% of the cone's volume) reduced Mount St. Helens' height by about 1300 ft m -2 on and left a crater 1 to 2 mi km 1 on wide and 2100 ft m on deep with its north end open in a huge breach.Harris 1988 211 More than 4000000000 board feet m3 of timber were damaged or destroyed, mainly by the lateral blast. At least 25% of the destroyed timber was salvaged after September 1980. Downwind of the volcano, in areas of thick ash accumulation, many agricultural crops, such as wheat, apples, potatoes, and alfalfa, were destroyed. As many as 1,500 elk and 5,000 deer were killed, and an estimated twelve million Chinook and Coho salmon fingerlings died when their hatcheries were destroyed. Another estimated 40,000 young salmon were killed when they swam through turbine blades of hydroelectric generators after reservoir levels were lowered along the Lewis River to accommodate possible mudflows and flood waters. In total, Mount St. Helens released 24 megatons TNT of thermal energy, seven 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. https://pubs.usgs.gov/fs/2000/fs036-00/ Mount St. Helens – From the 1980 Eruption to 2000, Fact Sheet 036-00 U.S. Geological Survey July 6, 2009 dead https://web.archive.org/web/20130512162409/http://pubs.usgs.gov/fs/2000/fs036-00/ May 12, 2013 In 2024, a study was conducted that provided an explanation for the observed phenomenon of an increase in the duration of the Lamb waves compared to the expected.Ponomarev, O.V. An analytical near-source shock wave model explaining anomalous periods of volcanic lamb waves: evidence from the 2022 hunga tonga eruption. Pure Appl. Geophys. (2025). https://doi.org/10.1007/s00024-025-03738-7 Uncertain death toll The death toll most commonly cited is 57, although two points of uncertainty remain. 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 named Paul Hiatt and Dale Thayer who were alive and well. However, they were unable to determine who reported Hiatt missing, and the person who was listed as reporting Thayer missing claimed she was not the one who had done so. Since the investigators could not thus verify that they were the same Hiatt and Thayer who were reported missing, the names remain listed among the presumed dead.Mountain Mystery: Some wonder if fewer people died in 1980 eruption http://tdn.com/news/mountain-mystery-some-wonder-if-fewer-people-died-in-eruption/article_0ef336b0-fb03-5958-b718-a2fab7cac17c.html Slape Leslie The Daily News April 22, 2005 December 10, 2015 https://web.archive.org/web/20200227235657/https://tdn.com/news/mountain-mystery-some-wonder-if-fewer-people-died-in-eruption/article_0ef336b0-fb03-5958-b718-a2fab7cac17c.html February 27, 2020Mt. St Helens Victims http://media.columbian.com/static/columbian/images/flatpage/msh/msh-victims.swf The Columbian December 10, 2015 https://web.archive.org/web/20160304031119/http://media.columbian.com/static/columbian/images/flatpage/msh/msh-victims.swf March 4, 2016 The second point regards three missing people who are not officially listed as victims: Robert Ruffle, Steven Whitsett, and Mark Melanson. Cowlitz County Emergency Services Management lists them as "Possibly Missing — Not 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 uncertainty into consideration, the direct death toll could be as low as 55 or as high as 60. When combined with the four indirect victims (two dying from vehicle accidents due to poor visibility, and two dying from heart attacks triggered by shovelling ash) those numbers range from 59 to 64. A year and a half after the eruption, the bodies of two young women, Marsha Anne Weatter and Katherine Jean Allen, 18 and 20 years old respectively, were discovered. They were believed to have been murdered six weeks before the eruption, rather than being killed by the events. Backpacks belonging to them had been found in July 1980, but a layer of ash deposited by the eruption may have hidden the bodies, also preventing animals disturbing the remains. An autopsy showed they had each been shot once.AP October 18, 1981 Evidence of 1980 Murders Hidden By Volcano https://www.nytimes.com/1981/10/18/us/evidence-of-1980-murders-hidden-by-volcano.html The New York Times 35 The murders of Weatter and Allen were later linked to serial killer Martin Lee Sanders.DeFede Jim 1990-07-11 Suspect in killings may face death penalty 3 Spokane Chronicle https://spokesman.newspapers.com/clip/83039785/martin-lee-sanders/ 2022-09-19 Ash damage and removal thumb|alt=Large yellow area on map|Map of ash distribution over the United States The ash fall created some temporary major problems with transportation, sewage disposal, and water treatment systems. Visibility was greatly decreased during the ash fall, closing many highways and roads. Interstate 90 from Seattle to Spokane was closed for a week and a half. Air travel was disrupted for between a few days and two weeks, as several airports in eastern Washington shut down because of ash accumulation and poor visibility. Over a thousand commercial flights were cancelled following airport closures. Fine-grained, gritty ash caused substantial problems for internal combustion engines and other mechanical and electrical equipment. The ash contaminated oil systems, clogged air filters, and scratched moving surfaces. Fine ash caused short circuits in electrical transformers, which in turn caused power blackouts. Removing and disposing of the ash was a monumental task for some Eastern Washington communities. State and federal agencies estimated that over 2400000 yd3 m3 on of ash, equivalent to about 900,000 tons in weight, were removed from highways and airports in Washington. The ash removal cost $2.2million and took ten weeks in Yakima. The need to remove ash quickly from transport routes and civil works dictated the selection of some disposal sites. Some cities used old quarries and existing sanitary landfills; others created dump sites wherever expedient. To minimize wind reworking of ash dumps, the surfaces of some disposal sites were covered with topsoil and seeded with grass. In Portland, the mayor eventually threatened businesses with fines if they failed to remove the ash from their parking lots.Painter, John Jr. The 1980s. The Oregonian, December 31, 1989. Cost thumb|alt=Lots of debris next to house|One of the 200 houses destroyed by the eruption A refined estimate of $1.1 billion ($US-GDP 1.1 1980 1 c billion in US-GDP) was determined in a study by the International Trade Commission at the request of the U.S. Congress. A supplemental appropriation of $951million for disaster relief was voted by Congress, of which the largest share went to the Small Business Administration, the U.S. Army Corps of Engineers, and the Federal Emergency Management Agency. Also, indirect and intangible costs of the eruption were incurred. Unemployment in the immediate region of Mount St. Helens rose 10-fold 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, 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 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 U.S. Forest Service and the State of Washington opened visitor centers and provided access for people to view the volcano's devastation. Later eruptions St. Helens produced an additional five explosive eruptions between May and October 1980. Through early 1990, at least 21 periods of eruptive activity occurred. The volcano remains active, with smaller, dome-building eruptions continuing into 2008. 1980–1991 thumb|upright|alt=Ash plume|Eruption on July 22, 1980 thumb|alt=Large mound of rock|The growing third dome on October 24, 1980 An eruption occurred on May 25, 1980, at 2:30am that sent an ash column 9 mi ft km on into the atmosphere.Harris 1988 211 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 avalanche debris, lahars, and other pyroclastic flows deposited by the May 18 eruption.Harris 1988 211 At 7:05 pm on June 12, a plume of ash billowed 2.5 mi km on above the volcano. At 9:09 pm, a much stronger explosion sent an ash column about 10 mi km on skyward.Harris 1988 212 This event caused the Portland area, previously spared by wind direction, to be thinly coated with ash in the middle of the annual Rose Festival. A dacite dome then oozed into existence on the crater floor, growing to a height of 200 ft m on and a width of 1200 ft m on within a week.Harris 1988 212 A series of large explosions on July 22 broke more than a month of relative quiet. The July eruptive episode was preceded by several days of measurable expansion of the summit area, heightened earthquake activity, and changed emission rates of sulfur dioxide and carbon dioxide. The first hit at 5:14pm as an ash column shot 10 mi km on and was followed by a faster blast at 6:25 pm that pushed the ash column above its previous maximum height in just 7.5 minutes.Harris 1988 212 The final explosion started at 7:01 pm, and continued over two hours.Harris 1988 212 When the relatively small amount of ash settled over eastern Washington, the dome built in June was gone.Harris 1988 213 Seismic activity and gas emission steadily increased in early August, and on August 7 at 4:26pm an ash cloud slowly expanded 8 mi km on into the sky.Harris 1988 213 Small pyroclastic flows came through the northern breach and a weaker outpouring of ash rose from the crater. This continued until 10:32 pm, when a second large blast sent ash high into the air, proceeding due north.Harris 1988 213 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 ten miles in the air, and created small, red-hot pyroclastic flows.Harris 1988 213 A third dome began to form within thirty minutes after the final explosion on October 18, and within a few days it was about 900 ft m on wide and 130 ft m on 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 3000 ft m on wide and 800 ft m on high.Harris 1988 213 Further eruptions occurred over a few months between 1989 and 1991. 2004–2008 2004–2008 volcanic activity of Mount St. Helens thumb|Plume of volcanic ash and steam in the October 2004 eruption The 2004–2008 volcanic activity of Mount St. Helens has been documented as a continuous eruption with a gradual extrusion of magma at the Mount St. Helens volcano. Starting in October 2004, a gradual building of a new lava dome happened. The new dome did not rise above the crater created by the 1980 eruption. This activity lasted until January 2008. Summary table Eruption summaryMay 18, 1980, eruption of Mount St. HelensElevation of summit: Before eruption: 9677 ft m 0 on After eruption: 8363 ft m 0 on Total removed: 1314 ft m 0 on Crater dimensions: East-West: 1.2 mi km 1 on North-South: 1.8 mi km 1 on Depth: 2084 ft m 0 on Crater floor elevation: 6279 ft m 0 on Eruption Date: May 18, 1980 Time of initial blast: 8:32 am Pacific Daylight Time (UTC−7) Eruption trigger: A magnitude 5.1 earthquake about 1 mi km 1 on beneath the volcano Landslide and debris avalanche Area covered: 23 sqmi km2 0 on Volume: (uncompacted deposits) 0.67 mi3 km3 on Depth of deposit: Buried North Fork Toutle River to average depth of 150 ft m 0 on with a maximum depth of 600 ft m 0 on Speed: 70 to 150 mph km/h 0 on Lateral blast Area covered: 230 sqmi km2 0 on; reached 17 mi km 0 on northwest of the crater Volume of deposit: (uncompacted deposits) 0.046 mi3 km3 on Depth of deposit: From about 3 ft m 0 on at volcano to less than 1 in cm 1 on at blast edge Speed: At least 300 mph km/h -1 on Temperature: As high as 660 F C -1 on Energy release: 24 megatons thermal energy (7 by blast, rest through release of heat) Trees blown down: 4000000000 board feet m3 on of timber (enough to build about 300,000 two-bedroom homes) Human fatalities: 55-60 (direct); four (indirect); 59-64 (total) Lahars Speed: About 10 to 25 mph km/h 0 on and over 50 mph km/h 0 on on steep flanks of volcano Damaged: 27 bridges, nearly 200 homes: Blast and lahars destroyed more than 185 mi km 0 on of highways and roads and 15 mi km 0 on of railways. Effects on Cowlitz River: Reduced carrying capacity at flood stage at Castle Rock from 76000 ft3 m3 on per second to less than 15000 ft3 m3 on per second. Effects on Columbia River: Reduced channel depth from 40 to 14 ft m 0 on; stranded 31 ships in upstream ports Eruption column and cloud Height: Reached about 80000 ft m -2 on in less than 15 minutes Downwind extent: Spread across U.S. in 3 days; circled Earth in 15 days Volume of ash:(based on uncompacted deposits) 0.26 mi3 km3 on Ash fall area: Detectable amounts of ash covered 22000 sqmi km2 -3 on Ash fall depth: 10 in cm 0 on at 10 mi km 0 on downwind (ash and pumice)1 in cm 1 on at 60 mi km 0 on downwind0.5 in cm 1 on at 300 mi km -1 on downwind Pyroclastic flows Area covered: 6 sqmi km2 0 on; reached as far as 5 mi km 0 on north of crater Volume and depth:(volume based on uncompacted deposits) 0.029 mi3 km3 on; multiple flows 3 to 30 ft m 0 on thick; cumulative depth of deposits reached 120 ft m 0 on in places Speed: Estimated at 50 to 80 mph km/h -1 on Temperature: At least 1300 F C -2 on Other Wildlife: The Washington State Department of Game estimated nearly 7,000 big game animals (deer, elk and bear) perished as well as all birds and most small mammals. Many burrowing rodents, frogs, salamanders and crawfish managed to survive because they were below ground level or water surface when the disaster struck. Fisheries: The Washington Department of Fisheries estimated that twelve million Chinook and Coho salmon fingerlings were killed when hatcheries were destroyed. Another estimated 40,000 young salmon were lost when forced to swim through turbine blades of hydroelectric generators as reservoir levels along the Lewis River were kept low to accommodate possible mudflows and flooding. Brantley and Myers, 1997, Mount St. Helens – From the 1980 Eruption to 1996 https://web.archive.org/web/20121005165357/http://vulcan.wr.usgs.gov/Volcanoes/MSH/Publications/FS070-97/framework.html October 5, 2012 : USGS Fact Sheet 070–97, accessed 2007-06-05; and Tilling, Topinka, and Swanson, 1990, Eruption of Mount St. Helens – Past, Present, and Future: USGS General Interest Publication, accessed 2007-06-05. Table compiled by Lyn Topinka, USGS/CVO, 1997 See also Volcanoes 1980s Washington (state) Cascade Volcanoes – High Cascades The Eruption of Mount St. Helens! (1980 film) – documentary movie about the eruption St. Helens (1981 film) - television movie about the eruption Geology of the Pacific Northwest Helenite – An artificial glass marketed as a gemstone, made by fusing the volcanic dust from Mount St. Helens' May 1980 eruption List of Cascade volcanoes List of volcanoes in the United States Pacific Ring of Fire References Citations http://blog.oregonlive.com/rosefestivalstories/2007/05/he_remembers_the_year_the_moun/print.html He Remembers the Year the Mountain Blew (1980) January 28, 2008 The Oregonian dead https://web.archive.org/web/20120829175127/http://blog.oregonlive.com/rosefestivalstories/2007/05/he_remembers_the_year_the_moun/print.html August 29, 2012 https://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/31521/31521.html Mount St. Helens Precursory Activity: March 15–21, 1980 2001 USGS https://web.archive.org/web/20121006015534/http://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/31521/31521.html October 6, 2012 https://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/5359/5359.html 2001 Mount St. Helens Precursory Activity: May 3–9, 1980 May 26, 2007 USGS https://web.archive.org/web/20130203044530/http://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/5359/5359.html February 3, 2013 Explosive Lessons of 25 Years Ago The Washington Post May 18, 2005 Blaine Harden A03 https://www.washingtonpost.com/wp-dyn/content/article/2005/05/17/AR2005051701275.html February 8, 2015 Sources Eruptions of Mount St. Helens: Past, Present, and Future https://vulcan.wr.usgs.gov/Volcanoes/MSH/Publications/MSHPPF/MSH_past_present_future.html December 5, 2010 Volcanoes: Crucibles of Change 1998 Fisher R. V. Heiken G. Hulen J. Princeton University Press 978-0-691-00249-1 Fire Mountains of the West: The Cascade and Mono Lake Volcanoes Harris Stephen L. 1988 Mountain Press Publishing Company Missoula, MT 978-0-87842-220-3 registration https://archive.org/details/firemountainsofw00harr https://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/intro.html https://web.archive.org/web/20121006015849/http://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/MSHThisWeek/intro.html October 6, 2012 May 1, 2001 Klimasauskas Ed Mount St. Helens Precursory Activity United States Geological Survey June 6, 2015 Tilling, Robert I. Topinka, Lyn Swanson, Donald A. 1990 https://vulcan.wr.usgs.gov/Volcanoes/MSH/Publications/MSHPPF/MSH_past_present_future.html Eruptions of Mount St. Helens: Past, Present, and Future U.S. Geological Survey December 5, 2010 dead https://web.archive.org/web/20111026174423/http://vulcan.wr.usgs.gov/Volcanoes/MSH/Publications/MSHPPF/MSH_past_present_future.html October 26, 2011 (adapted public domain text) Topinka Lyn https://web.archive.org/web/20071218051528/http://vulcan.wr.usgs.gov/Volcanoes/MSH/SlideSet/ljt_slideset.html https://vulcan.wr.usgs.gov/Volcanoes/MSH/SlideSet/ljt_slideset.html Mount St. Helens: A General Slide Set Cascades Volcano Observatory, U.S. Geological Survey May 10, 2007 December 18, 2007 Further reading Eruption of Mount St. Helens National Geographic January 1981 159 1 3–65 0027-9358 643483454 Mount St. Helens Aftermath National Geographic Rowe Findley 713–733 160 6 December 1981 0027-9358 643483454 External links 1980 eruption of Mount St. Helens http://www.idreamof.com/disaster/vic_msh_fm.html Mt. St. Helens Volcano Victims I Dream of Genealogy December 15, 2004 dead https://web.archive.org/web/20070527160122/http://www.idreamof.com/disaster/vic_msh_fm.html May 27, 2007 List of victims with biographical details USGS: Mount St. Helens 1980 Debris Avalanche Deposit https://web.archive.org/web/20130129085331/http://vulcan.wr.usgs.gov/Volcanoes/MSH/DebrisAval/description_msh_debris_aval.html January 29, 2013 USDA Forest Service: Mount St. Helens VolcanoCam Pre-1980 Eruptive History of Mount St. Helens, Washington USGS: Before, During, and After May 18, 1980 https://web.archive.org/web/20130129085503/http://vulcan.wr.usgs.gov/Volcanoes/MSH/Images/MSH80/framework.html#may_18_1980 January 29, 2013 Boston.com – The Big Picture – 30 years later gov.archives.arc.13364 Eruption of Mount St. Helens, 1980 (1981) gov.archives.arc.13504 This place in time: The Mount St. Helens story (1984) Aerial pictures of the July 22nd, 1980, secondary eruption News reports https://web.archive.org/web/20201206023356/http://www.fuzzymemories.tv/index.php?m=xxhelensxx December 6, 2020 at The Museum of Classic Chicago Television Mount St. Helens 1980 Mount St. Helens 1980 Mount St. Helens 1980 Mount St. Helens Mount St. Helens 1980 Mount St. Helens Category:Cascade Volcanoes Category:Gifford Pinchot National Forest Category:Mount St. Helens Mount St. Helens 1980 Category:Volcanism of Washington (state) Category:1980 natural disasters Category:1980s landslides Category:May 1980 in the United States Category:Megatsunamis St. Helens Category:Volcanic eruptions in the United States Category:Phreatic eruptions Category:Plinian eruptions Category:Peléan eruptions Category:Volcanic tsunamis Category:Sector collapses