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49 free Mount St. Helens trivia questions with answers — geography quiz, new questions added Aug 2026.
This Mount St. Helens trivia quiz covers the Cascade volcano whose 1980 eruption remains the most economically destructive volcanic event in American history. The easy questions cover the state, the year, the death toll and the mountain's Fujiyama-like shape before the blast. From there the quiz moves through the eruption itself: the March earthquake, the bulge on the north face, the 5.1 quake at 8:32 on a Sunday morning, the largest debris avalanche in recorded history, the lateral blast, the ash that reached Edmonton and the 1,300 feet the summit lost. The hard end covers the Kalama and Goat Rocks eruptive periods, the 1831 ash that tinted the sun over Nat Turner's Virginia, George Vancouver's diplomat friend, the Klickitat legend of Loowit and the Bridge of the Gods, Harry R. Truman, David Johnston's last radio call, Robert Landsburg's camera, the Crater Glacier that grew inside the breach, the whaleback and the slab of the 2004-2008 eruption, and the returning mountain goats and beavers. Every answer was checked against the encyclopaedia entry on Mount St. Helens before publishing and the supporting sentence is stored with each question. Our volcanoes and national parks quizzes are natural next stops.
30 of 49 questions with answers and explanations. Play the quiz
Q 01In which US state is Mount St. Helens?
Washington
Mount St. Helens is in Washington, in Skamania County, about 50 miles northeast of Portland, Oregon and 96 miles south of Seattle.
Q 02On which day of the week did Mount St. Helens erupt on 18 May 1980?
Sunday
The eruption came at 8:32 am on Sunday, 18 May 1980; because it was a weekend, most loggers were away from the blast zone.
Q 03How many people were killed by the 1980 eruption?
57
The 18 May 1980 eruption killed 57 people, most by asphyxiation from hot ash; the bodies of some victims were never found.
Q 04What was the magnitude of the earthquake that triggered the collapse of the mountain's north face?
5.1
A magnitude 5.1 earthquake at 8:32 am on 18 May 1980 shook loose the bulging north face, triggering the largest landslide in recorded history.
Q 05By roughly how much did the eruption reduce the height of the summit?
About 1,300 feet
The summit dropped about 1,300 feet, from 9,677 to 8,363 feet, leaving a crater open to the north.
Q 06What shape is the crater left by the 1980 eruption?
Horseshoe
The blast left a horseshoe-shaped crater about a mile wide, its north side breached where the landslide carried the summit away.
Q 07What rating did the 1980 eruption receive on the Volcanic Explosivity Index?
5
The eruption rated 5 on the Volcanic Explosivity Index, a Plinian event that drove ash into the stratosphere and released about 1.5 million tonnes of sulphur dioxide.
Q 08How high did the ash plume rise on 18 May 1980?
12 to 16 miles
The column climbed 12 to 16 miles, about 80,000 feet, within 15 minutes, then streamed east at roughly 60 mph and dusted Idaho by noon.
Q 09In which Canadian city was ash from the eruption found on cars and roofs the next morning?
Edmonton
High-altitude winds carried fine ash northeast into Canada, and a light dusting settled on cars and rooftops in Edmonton, Alberta, roughly 600 miles from the volcano.
Q 10What is the term for the volcanic mudflows that raced down the Toutle and Cowlitz rivers?
Lahars
Lahars are fast mudflows of volcanic debris and meltwater; those on 18 May 1980 choked the Cowlitz and Columbia rivers, cutting the Columbia's shipping channel from 40 feet to 14 feet deep.
Q 11Over roughly what area did the pyroclastic flow flatten vegetation and buildings?
230 square miles
The lateral blast flattened forest across about 230 square miles, killing nearly 7,000 big-game animals and an estimated 12 million hatchery salmon fingerlings.
Q 12What was the name of the 83-year-old lodge owner who refused to evacuate and died in the eruption?
Harry R. Truman
Harry R. Truman, 83, had run his lodge on Spirit Lake for more than 50 years and refused to leave; he died in the blast and his body was never found.
Q 13What were volcanologist David Johnston's last radioed words from Coldwater Ridge?
"Vancouver! Vancouver! This is it!"
Q 21What nickname did the symmetrical, snow-covered pre-1980 cone earn?
Fujiyama of America
Its graceful symmetry earned it the nickname 'Fujiyama of America'; at 9,677 feet it was Washington's fifth-highest peak before 1980.
Q 22How many named glaciers covered the mountain just before the 1980 eruption?
11
The mountain carried 11 named glaciers before 18 May 1980; the eruption destroyed most of them, though a brand-new Crater Glacier later grew inside the breach.
Q 23What split the Crater Glacier into two arms from 2004?
A new lava dome
A new lava dome, growing from October 2004, pushed up through the Crater Glacier, splitting it into east and west arms that later crept around the dome and rejoined.
David Johnston, 30, radioed 'Vancouver! Vancouver! This is it!' to the USGS office in Vancouver, Washington, seconds before the lateral blast swept his post; Coldwater Ridge was later renamed Johnston Ridge.
Q 14How did photographer Robert Landsburg preserve his pictures of the approaching ash cloud?
He lay on top of his backpack to shield the film
Robert Landsburg rewound his film, packed the camera in his backpack and lay on top of his backpack to shield the film; his body and the intact film were found on 4 June 1980.
Q 15Which US president compared the devastation unfavourably with the surface of the moon?
Jimmy Carter
Jimmy Carter toured the blast zone on 22 May 1980 and said the moon 'looks more like a golf course compared to what's up there'.
Q 16What happened to the compasses of the film crew dropped on the mountain on 23 May 1980?
They spun in circles
The crew's compasses were useless: they spun in circles, and the lost crew survived a second eruption on 25 May before National Guard helicopters rescued them on 27 May 1980.
Q 17What artificial gemstone is made from Mount St. Helens ash?
Helenite
Helenite is a man-made glass fused from Mount St. Helens ash, usually a vivid green; the ash was also used in ceramic glazes and sold as curios.
Q 18After whom did George Vancouver name the mountain in 1792?
A British diplomat, Baron St Helens
Vancouver named it on 20 October 1792 for his friend Alleyne FitzHerbert, Baron St Helens, a British diplomat then serving as ambassador to Spain.
Q 19What is the Klickitat name for the mountain, meaning 'smoking or fire mountain'?
Louwala-Clough
The Klickitat called it Louwala-Clough, 'smoking mountain'; in their legend the maiden Loowit was turned into the volcano after the brothers Wy'east and Pahto fought over her.
Q 20In the Bridge of the Gods legend, which mountain did the proud suitor Wy'east become?
Mount Hood
The proud Wy'east became Mount Hood, south of the Columbia River, while his grieving rival Pahto bowed his head and became a peak to the east.
Q 24Mount St. Helens is one segment of which Pacific-wide belt of volcanoes?
The Ring of Fire
Mount St. Helens belongs to the Ring of Fire, the chain of volcanoes around the Pacific; it sits in the Cascade Arc, fed by the Juan de Fuca plate subducting beneath North America.
Q 25Which Cascade peak, 34 miles to the east, is considered Mount St. Helens's 'brother'?
Adams
Mount Adams, 34 miles to the east, is often called St. Helens's 'brother'; both stand about 50 miles from Mount Rainier, the highest Cascade peak.
Q 26Which eruptive period, from around 1480, saw the volcano reach its greatest height?
Kalama
The Kalama period opened around 1480 with an eruption several times larger than 1980's, and by its close about 1647 the summit had reached its greatest height.
Q 27The 57-year eruptive period that began in 1800 is named after which feature?
The Goat Rocks dome
The Goat Rocks period (1800-1857) takes its name from the Goat Rocks dome, a lava dome on the north flank destroyed in the 1980 landslide; it is the first period with both oral and written records.
Q 28Which lava type built the domes inside the crater after 1980?
Dacite
The 1980-86 dome and the 2004-08 extrusion are dacite, a silica-rich, viscous lava that piles up in the crater instead of flowing far.
Q 29In 1829 Hall J. Kelley campaigned to rename the entire Cascade chain as what?
The President's Range
Kelley's 1829 scheme would have renamed the Cascades the President's Range, with each major peak named for a US president; St. Helens was to become Mount Washington.
Q 30What was the name given to the lava spine extruded from the crater dome in 2004-2005?
The whaleback
Geologists dubbed the smooth spine of dacite the 'whaleback'; its tip broke off on 2 July 2005, and a later feature, half a football field across, was called the slab or fin.