Mount St. Helens

• 1. Introduction

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  At Mount St. Helens in May 1980, a 30-year-old volcanologist named David A. Johnston made a radio call from Coldwater Ridge. He was stationed there to watch the mountain. Moments before the pyroclastic flow struck his position, he transmitted his last words: "Vancouver! Vancouver! This is it!" His body was never found.

  The volcano he was watching is an active stratovolcano in Skamania County, Washington. It lies 83 km northeast of Portland, Oregon, and 158 km south of Seattle. It is part of the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire. The eruption that killed Johnston became the most economically destructive volcanic event in United States history.

  Yet the mountain had a long life before that day, and it has kept living since. Why do several peoples have different names and stories for the same peak? What built a volcano so young and so restless? How did a cone admired for its perfect shape lose its summit, and what did scientists learn from the wreckage? And is the mountain finished?

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• 2. Loowit and Her Suitors

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  The Klickitat people tell of a chief of all the gods who traveled down the Columbia River from the Far North with his two sons, Pahto and Wy'east. Pahto is also called Klickitat. At the place now called The Dalles, they found land so beautiful that the brothers quarreled over it. To settle the dispute, their father shot one arrow to the north and one to the south. Pahto followed the northern arrow and settled there, and Wy'east did the same in the south. The father then built the Bridge of the Gods so the family could meet from time to time.

  Loowit enters the story as a beautiful maiden with whom both sons fell in love. She could not choose between them. The two young chiefs fought, burying villages and forests, and the earth shook so violently that the great bridge fell into the river. Its fall created the cascades of the Columbia River Gorge. As punishment, the chief of the gods struck down all three and turned each into a mountain where they fell.

  Wy'east, head lifted in pride, became Mount Hood. Pahto, head bent toward his fallen love, became Mount Adams. Loowit became Mount St. Helens. The two volcanoes St. Helens and Adams, about 34 mi apart, are still considered "brother and sister" mountains.

  The Klickitat call the mountain Louwala-Clough, which means "smoking or fire mountain." The Sahaptin call it Loowit. To the Cowlitz it is Lawetlat'la, roughly "the smoker." The Cowlitz and Yakama tribes hold the ground above its tree line to be of exceptional spiritual significance. The mountain features prominently in their creation story and in some of their songs and rituals. Over 12000 acres, roughly bounded by the Loowit Trail, are listed on the National Register of Historic Places.

  Other peoples named the peak for what they saw. The Upper Chehalis called it nšh'ák'w, meaning "water coming out." A Kiksht term, aka akn, means "snow mountain."

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• 3. Forty Thousand Years of Eruptions

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  Beneath the Cascade Range, a dense oceanic plate is sinking under the North American Plate, a process called subduction. As the slab descends, heat and pressure squeeze water out of its minerals. That water rises into the mantle above and causes some of it to melt. The new magma climbs through fractures and faults and by melting surrounding rock, which changes its chemistry. Some of it reaches the surface and builds the Cascade Volcanic Arc, a band from southwestern British Columbia to Northern California.

  Under St. Helens, magma has gathered in two chambers. One lies about 5 to 12 km below the surface, and the other about 12 to 40 km down. The deeper chamber may be shared with Mount Adams and the Indian Heaven volcanic field.

  Compared with its Cascade neighbors, St. Helens is young. It formed only within the past 40,000 years, and the summit cone standing before 1980 began rising about 2,200 years ago. Across the Holocene, the last 10,000 years or so, it has been the most active volcano in the range.

  Geologists divide its life into named stages. The ancestral stages are Ape Canyon, Cougar and Swift Creek. The modern period, which began about 2500 BC, is the Spirit Lake Stage. Growth began 37,600 years ago during Ape Canyon, with eruptions of hot pumice and ash. A large mudflow rushed down 36,000 years ago, and mudflows would mark every later cycle. About 17,000 relatively quiet years followed.

  The Cougar Stage began 20,000 years ago and lasted 2,000 years, with pyroclastic flows and dome growth. Another 5,000 years of dormancy came next. The Swift Creek period then brought more flows, domes and blankets of tephra, and it ended 8,000 years ago.

  Around 2500 BC, after about 4,000 quiet years, the Smith Creek period began with huge outpourings of ash and yellowish-brown pumice. An eruption in 1900 BC was the largest known from St. Helens in the Holocene. It left deposits 18 in deep, 50 mi away in what is now Mount Rainier National Park. Trace deposits turned up as far away as Banff National Park in Alberta and eastern Oregon. This cycle may have thrown out up to 2.5 mi3 of material.

  The Pine Creek period, from about 1200 BC to 800 BC, brought smaller eruptions and nearly red hot pyroclastic flows that settled in nearby valleys. Sometime between 1000 BC and 500 BC, a mudflow partly filled 40 mi of the Lewis River valley.

  About 400 BC, the Castle Creek period changed the recipe, adding olivine and basalt to the lava. The pre-1980 summit cone began to form then. A flow around 100 BC ran all the way into the Lewis and Kalama river valleys. The Cave Basalt, known for its lava tubes, flowed up to 9 mi from its vents. During the first century, mudflows ran 30 mi down the Toutle and Kalama valleys and may have reached the Columbia River.

  The Sugar Bowl period was short. It produced the only unequivocal sideways blast known from the mountain before 1980.

  After roughly 700 quiet years, the Kalama period opened in about 1480 with pale gray dacite pumice and ash. That eruption was several times larger than the one in 1980. A second, in 1482, rivaled the 1980 eruption in volume. Ash lay 3 ft thick 6 mi northeast of the volcano and 2 in deep 50 mi away. By the time the cycle ended in about 1647, St. Helens had reached its greatest height and its highly symmetrical form. The mountain then slept for 150 years.

  Before 1980, it ranked as the fifth-highest peak in Washington. Its symmetry and wide covering of snow and ice earned it, from some, the nickname "Fujiyama of America."

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• 4. Eyewitnesses and Rumors

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  In 1800, the quiet broke with the start of the 57-year Goat Rocks period, named for a dome on the northeast flank. It is the first period with both oral and written records. Geologists determined only much later that the eruption had happened, so the Nespelem tribe of northeastern Washington supposedly suffered because of it. Alarmed by "dry snow," they danced and prayed rather than gather food, and they starved that winter.

  Europeans had already seen the mountain by then. Royal Navy Commander George Vancouver and the officers of HMS Discovery made the first recorded sighting on the 19th of May 1792. Vancouver named it on the 20th of October 1792, as it came into view while the Discovery entered the mouth of the Columbia River. The name honors Alleyne FitzHerbert, 1st Baron St Helens, a British diplomat and a friend of Vancouver.

  In late 1805 and early 1806, the Lewis and Clark Expedition spotted the peak from the Columbia River and reported no eruption. They did report quicksand and clogged channels at the mouth of the Sandy River near Portland. That suggested an eruption of Mount Hood in the preceding decades. In 1829, Hall J. Kelley led a campaign to rename the Cascades the President's Range, with each major peak renamed for a former president. St. Helens would have become Mount Washington.

  The eruptions of 1831 may have tinted the sun bluish-green over Southampton County, Virginia, on the 13th of August. Nat Turner took that as the final signal to launch the largest slave rebellion in the United States. In March 1835, Meredith Gairdner, working for the Hudson's Bay Company at Fort Vancouver, made the first authenticated non-Indigenous eyewitness report of an eruption. His letter appeared in the Edinburgh New Philosophical Journal in January 1836. In 1841, James Dwight Dana of Yale saw the quiet peak from off the mouth of the Columbia.

  Then came the so-called Great Eruption, in late fall or early winter of 1842. Settlers and missionaries watched a small outburst throw up large ash clouds, and mild explosions followed for 15 years. Josiah Parrish, in Champoeg, Oregon, saw it on the 22nd of November 1842. The ash may have reached The Dalles, 48 mi southeast. Artists caught the mountain too. British lieutenant Henry J. Warre sketched the eruption in 1845, and the Canadian painter Paul Kane made watercolors of the gently smoking peak two years later.

  Not every tale holds up. In October 1843, the future California governor Peter H. Burnett told a very likely apocryphal story of an Indigenous man burned by lava or hot ash while hunting deer. The man supposedly sought treatment at Fort Vancouver, but the fort's commissary steward, Napoleon McGilvery, disclaimed any knowledge of it.

  On the 17th of April 1857, a Steilacoom, Washington, newspaper called the Republican 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 shows it was small, and it closed the Goat Rocks period.

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• 5. The Day the Mountain Fell

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  On the 20th of March 1980, a magnitude 4.2 earthquake rattled Mount St. Helens. On the 27th, steam venting began. By the end of April, the north side of the mountain had begun to bulge. Then at 8:32 am on the 18th of May, a magnitude 5.1 earthquake triggered the collapse of the north face. It was the largest known debris avalanche in recorded history, at 2.5 km3 in volume.

  With the flank gone, the magma inside burst out as a large pyroclastic flow. It flattened vegetation and buildings across 230 square miles. More than 1.5 million metric tons of sulfur dioxide entered the atmosphere. Scientists rated the eruption a 5 on the Volcanic Explosivity Index and classed it as Plinian. The old Goat Rocks dome, near the site of the bulge, was obliterated.

  The collapsed flank mixed with ice, snow and water to form lahars, or volcanic mudflows. They surged many miles down the Toutle and Cowlitz Rivers and destroyed bridges and lumber camps. In all, 3900000 yd3 of material was carried 17 mi south into the Columbia River.

  For more than nine hours, a vigorous plume of ash climbed 12 to 16 mi above sea level. It drifted east at an average of 60 mph and reached Idaho by noon. By the next morning, ash covered cars and roofs as far away as Edmonton, Alberta. By about 5:30 pm, the vertical column had shrunk, though smaller outbursts went on through the night and for several days.

  The eruption released 24 megatons of thermal energy and threw out more than 0.67 mi3 of material. The summit dropped from 9677 to 8363 ft. That left a horseshoe-shaped crater 2,084 ft deep, open in a huge breach at its north end. Fifty-seven people died, along with nearly 7,000 big-game animals (deer, elk and bear) and an estimated 12 million fish from a hatchery. More than 200 homes, 47 bridges, 15 mi of railways and 185 mi of highway were destroyed. Among the dead were a lodge owner who refused to leave and a photographer who aimed his camera at the cloud.

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• 6. Stubborn Lodge Keepers and Cameras

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  Harry R. Truman, aged 83, had lived near the mountain since 1929 and ran the Spirit Lake Lodge. Local authorities repeatedly pleaded with him to leave before the eruption, and he refused. His decision drew heavy media attention. His body was never found.

  Robert Landsburg, a photographer, took pictures of the approaching ash cloud. He then put his camera in his backpack and lay on top of it to protect the film. His body and the camera were found on the 4th of June 1980. The photographs survived and gave geologists valuable documentation of the eruption.

  The date mattered. The eruption fell on a Sunday. Had it come one day later, loggers would have been at work, and the death toll could have been far higher.

  President Jimmy Carter surveyed the damage and offered a comparison: "Someone said this area looked like a moonscape, but the moon looks more like a golf course compared to what's up there."

  On the 23rd of May, a film crew led by the Seattle filmmaker Otto Seiber was dropped by helicopter onto St. Helens to document the destruction. Their compasses spun in circles, and they quickly became lost. A second eruption came on the 25th of May. National Guard helicopter pilots rescued the crew two days later. Their film, The Eruption of Mount St. Helens!, later became a popular documentary.

  The ash did harm far from the mountain. Ashfall caused approximately $100 million of damage to agriculture downwind in Eastern Washington. Yet apple and wheat production were higher in the 1980 growing season, possibly because ash helped soil retain moisture. Ash also became a raw material for the artificial gemstone helenite and for ceramic glazes, and it was sold as a tourist curio.

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• 7. Life After the Blast

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  More than half of the scientific papers on how ecosystems respond to volcanic eruptions come from studies of Mount St. Helens. Research began immediately after the eruption, and the blast did not sterilize the area nearby. Its most important concept may be the biological legacy, meaning the survivors of a catastrophic disturbance. They can be living plants that endured ashfall, organic debris or surviving patterns from before. Such legacies strongly shape how the ecosystem rebuilds.

  Before 1980, an average of 2373 mm of precipitation fell each year at Spirit Lake. Dense forest of western hemlock, Douglas fir and western redcedar rose to 900 m. Above that, Pacific silver fir dominated up to 1300 m. The treeline sat unusually low, at about 1340 m, because earlier volcanic disturbance had held it down. Roosevelt elk, black-tailed deer, American black bear and mountain lion lived there, and mountain goats held the higher ground.

  Some species from each trophic level survived, so food webs rebuilt relatively quickly. Larger animals fared worse. Mountain goats, elk, deer, black bear and cougars were completely decimated, and the goat population was eliminated. Each larger mammal eventually migrated back, though many elk starved in the following winters for lack of forage. By 2014, the goats numbered 65. In 2015, there were 152. The Cowlitz Tribe, whose members historically gathered tufts of wool the goats shed, helps monitor the recovering herd.

  Aquatic life took a different path. Ash fed the lakes and let life multiply rapidly, and six years after the eruption most lakes had returned to their normal state.

  Ice changed too. Eleven named glaciers had covered the old cone: Wishbone, Loowit, Leschi, Forsyth, Nelson, Ape, Shoestring, Swift, Dryer, Toutle and Talus. Only Shoestring revived somewhat. During the winter of 1980-81, a new glacier appeared inside the crater, now officially named Crater Glacier and formerly the Tulutson Glacier. Shadowed by crater walls and fed by snow and avalanches, it thickened by 14 ft per year. By 2004 it covered about 0.36 square miles.

  By 2006, its ice averaged 300 ft thick and reached 650 ft at the deepest point. Its volume matched that of all the pre-1980 glaciers combined, though every bit of the ice is post-1980. New domes pushed its lobes aside from 2004, but the ends kept advancing, and in late May 2008 the two lobes joined to surround the domes completely.

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• 8. Watching and Climbing

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  On the 11th of October 2004, magma reached the surface of Mount St. Helens, and a new dome began to grow on the south side of the old one. Fragile features rose and crumbled. One was a lava spine nicknamed the "whaleback," whose tip broke off on the 2nd of July 2005. A slab called the "fin," about half the size of a football field, was forced up as fast as 6 ft per day. On the 8th of March 2005, a 36000 ft plume of steam and ash, visible from Seattle, accompanied a magnitude 2.5 earthquake.

  On the 22nd of October 2006, at 3:13 pm PST, a magnitude 3.5 earthquake broke loose Spine 7. A plume rose 2000 ft over the crater's western rim and quickly dissipated. In January 2008, steam seeped from a fracture on the dome and seismic activity reached its highest level since 2004. Scientists paused work in the crater, but the risk of a major eruption was judged low. On the 10th of July 2008, after more than six months without activity, the eruption was declared over.

  Geologists predict that future eruptions will be more destructive, because the configuration of the domes demands more pressure to erupt. A large lahar is likely on branches of the Toutle River, with possible damage in inhabited areas along the I-5 corridor. The United States Geological Survey rates the volcano "very high threat," and the Cascades Volcano Observatory monitors it closely.

  In 1982, President Ronald Reagan and Congress created the Mount St. Helens National Volcanic Monument, a 110000 acre area within the Gifford Pinchot National Forest. The Forest Service reopened the mountain to climbing in 1987 and has required permits since. Renewed activity closed it in 2004, and climbers returned on the 21st of July 2006. Anyone above 4800 ft needs a permit year-round.

  The Monitor Ridge Route is the usual summer climb. It gains about 4600 ft in about 5 mi, and most climbers finish the round trip in 7 to 12 hours. The Worm Flows Route is the standard winter climb, gaining about 5700 ft over about 6 mi. Danger remains. On the 14th of April 2008, the snowmobiler John Slemp fell 1,500 feet into the crater when a snow cornice gave way. He survived with minor injuries and was rescued by helicopter. In February 2010, a climber fell from the rim and died.

  Washington now marks May as "Volcano Awareness Month." On the 14th of May 2023, a mudslide and debris flow called the South Coldwater Slide destroyed the 85 ft Spirit Lake Outlet Bridge on State Route 504. It cut off access to the Johnston Ridge Observatory, named for the volcanologist who had radioed his last words from the ridge nearby.

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