How far did the ash from Mount St. Helens travel?

The May 18, 1980 eruptive column at Mount St. Helens fluctuated in height through the day, but the eruption subsided by late afternoon. By early May 19th, the eruption had stopped. By that time the ash cloud had spread to the central United States.

Two days later, even though the ash cloud had become more diffuse, fine ash was detected by systems used to monitor air pollution in several cities of the northeastern United States. Some of the ash drifted around the globe within about 2 weeks.

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How far would ash travel if Yellowstone had a large explosive eruption?

Knowledge about past eruptions of Yellowstone combined with mathematical models of volcanic ash dispersion help scientists determine where and how much ashfall will occur in possible future eruptions. During the three caldera-forming eruptions that occurred between 2.1 million and 640,000 years ago, tiny particles of volcanic ash covered much of...

Does ash ever erupt from Kīlauea Volcano??

Kīlauea Volcano is renowned for its relatively benign eruptions of fluid lava flows. Therefore, many people were surprised by the small explosions that occurred in Halema`uma`u Crater in 2008 and 2018, and even more surprised to learn that volcanic ash was being erupted from a new gas vent. However, ash emissions from Halema`uma`u Crater are part...

How would an eruption of Mount Rainier compare to the 1980 eruption of Mount St. Helens?

Eruptions of Mount Rainier usually produce much less volcanic ash than do eruptions at Mount St. Helens. However, owing to the volcano's great height and widespread cover of snow and glacier ice, eruption-triggered debris flows ( lahars ) at Mount Rainier are likely to be much larger -- and will travel a greater distance -- than those at Mount St...

How much ash was there from the May 18, 1980 eruption of Mount St. Helens?

During the 9 hours of vigorous eruptive activity on May 18, 1980, about 540 million tons of ash from Mount St. Helens fell over an area of more than 22,000 square miles. The total volume of the ash before its compaction by rainfall was about 0.3 cubic mile, equivalent to an area the size of a football field piled about 150 miles high with fluffy...

How old is Mount St. Helens?

The eruptive history of Mount St. Helens began about 40,000 years ago with dacitic volcanism, which continued intermittently until about 2,500 years ago. This activity included numerous explosive eruptions over periods of hundreds to thousands of years, which were separated by apparent dormant intervals ranging in length from a few hundred to...

What is the origin of the name "Mount St. Helens"?

Some Indians of the Pacific Northwest variously called Mount St. Helens 'Louwala-Clough,' or 'smoking mountain.' The modern name, Mount St. Helens, was given to the volcanic peak in 1792 by seafarer and explorer Captain George Vancouver of the British Royal Navy. He named it in honor of fellow countryman Alleyne Fitzherbert, who held the title ‘...

How many eruptions have there been in the Cascades during the last 4,000 years?

Eruptions in the Cascades have occurred at an average rate of one to two per century during the last 4,000 years. Future eruptions are certain. Learn more: Eruptions in the Cascade Range During the Past 4,000 Years USGS Cascades Volcano Observatory

How high was Mount St. Helens before the May 18, 1980 eruption? How high was it after?

Before May 18, 1980, Mount St. Helens ' summit altitude of 9,677 feet (2,950 meters) made it only the fifth highest peak in Washington State. It stood out handsomely, however, from surrounding hills because it rose thousands of feet above them and had a perennial cover of ice and snow. The peak rose more than 5,000 feet (1,524 meters) above its...
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Date published: May 6, 2019

The National Volcano Early Warning System (NVEWS) will help USGS better monitor nation’s most dangerous volcanoes

In September 2004, USGS scientists detected sudden, but unmistakable, signs that Mount St. Helens was waking up. Volcano monitors had picked up the occurrence of hundreds of small earthquakes and other signals that the volcano’s crater floor had begun to rise. Within a week, several eruptions blasted clouds of ash into the atmosphere, and soon after, a new lava dome emerged in the crater.

Date published: December 19, 2018

Which U.S. volcanoes pose a threat?

USGS Volcanic Threat Assessment updates the 2005 rankings.

Date published: September 18, 2018

Science for a Risky World: A USGS Plan for Risk Research and Applications – USGS publishes strategic plan for examining risk

USGS explores opportunities to advance its capabilities in risk assessment, mitigation, and communication in new strategic plan.

Date published: September 3, 2018

Scientists Discover New Clues to Mount St. Helens Unusual Location

The atypical location of Mount St. Helens may be due to geologic structures that control where deep magmas can rise through the crust, as suggested by new findings published today in Nature Geoscience.

Date published: May 18, 2017

Ever Vigilant: USGS Marks the 37th Anniversary of Mount St. Helen's Eruption and the 35th Anniversary of the Cascades Volcano Observatory

Today, in 1980, Mount St. Helens unleashed the most devastating eruption in U.S. history. Two years later, USGS founded the Cascades Volcano Observatory to monitor Mount St. Helens and all the Cascades Volcanoes.

Date published: May 1, 2017

May is Volcano Preparedness Month in Washington State

May is Volcano Preparedness Month in Washington, providing residents an opportunity to become more familiar with volcano hazards in their communities and learn about steps they can take to reduce potential impacts.

Date published: February 1, 2016

EarthWord – Nuée Ardente

A nuée ardente is a turbulent, fast moving cloud of hot gas and ash erupted from a volcano. 

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February 22, 2018

PubTalk 2/2018 — USGS Cascades Volcano Observatory

Title: The USGS Cascades Volcano Observatory - Research, monitoring, and the science of preparing society for low-probability, high-consequence events

  • Volcanoes in the Cascade Range erupt twice per century on average, with eruptions often lasting for years.
  • Although eruptions are generally not as high-consequence as large earthquakes, they are still
...
Attribution: Natural Hazards
May 26, 2016

Forecasting Ashfall Impacts from a Yellowstone Supereruption

  • Yellowstone is one of a few dozen volcanoes on earth capable of "supereruptions" that expel more than 1,000 cubic km of ash and debris.
  • The plumes from such eruptions can rise 30 to 50 km into the atmosphere, three to five times as high as most jets fly.
  • Yellowstone has produced three supereruptions in the past 2.1 million years. The most recent was
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Attribution: Yellowstone
Mount St. Helens before and after 1980 eruption
May 9, 2016

Mount St. Helens before and after 1980 eruption

Left: Before the eruption of May 18, 1980, Mount St. Helens' elevation was 2,950 m (9,677 ft). View from the west, Mount Adams in distance. S. Fork Toutle River is valley in center of photo.

Right: Mount St. Helens soon after the May 18, 1980 eruption, as viewed from Johnston's Ridge.

video thumbnail: Volcano Hazards
July 30, 2012

Volcano Hazards

The United States has 169 active volcanoes. More than half of them could erupt explosively, sending ash up to 20,000 or 30,000 feet where commercial air traffic flies. USGS scientists are working to improve our understanding of volcano hazards to help protect communities and reduce the risks.

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  • Volcanoes: Monitoring Volcanoes
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May 9, 2012

Volcano Web Shorts 5 - Volcanic Ash Impacts

Volcanic ash is geographically the most widespread of all volcanic hazards. USGS geologist Larry Mastin describes how volcanic ash can disrupt lives many thousands of miles from an erupting volcano. The development of ash cloud models and ash cloud disruption to air traffic is highlighted.

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Volcano Web Shorts 4 - Instruments

USGS technologist Rick LaHusen describes how the development and deployment of instruments plays a crucial role in mitigating volcanic hazards.

Attribution: Volcano Hazards
video thumbnail: Mount St. Helens: May 18, 1980
May 10, 2010

Mount St. Helens: May 18, 1980

USGS scientists recount their experiences before, during and after the May 18, 1980 eruption of Mount St. Helens. Loss of their colleague David A. Johnston and 56 others in the eruption cast a pall over one of the most dramatic geologic moments in American history.

video thumbnail: Mount St. Helens: A Catalyst for Change
May 10, 2010

Mount St. Helens: A Catalyst for Change

The May 18, 1980 eruption of Mount St. Helens triggered a growth in volcano science and volcano monitoring. Five USGS volcano observatories have been established since the eruption. With new technologies and improved awareness of volcanic hazards USGS scientists are helping save lives and property across the planet.

December 31, 2006

Mount St. Helens 2004-2008 Eruption: A Volcano Reawakens

Mount St. Helens reawakened in late September 2004. Small magnitude earthquakes beneath the 1980-1986 lava dome increased in frequency and size, and a growing welt formed on the southeast margin of the previous lava dome and nearby portions of Crater Glacier. On October 1, 2004, the first of several explosions shot a plume of volcanic ash and gases from a vent on the

...
December 31, 2004

Mount St. Helens eruption highlights: September 2004 - May 2005

Compilation video of significant events from the dome-building eruption at Mount St. Helens, from October 1, 2004 to March 15, 2005, including steam and ash eruptions, growth of lava spines, helicopter deployment of monitoring equipment, collection of lava samples, and FLIR thermal imaging of rock collapse on lava dome.

  1. Eruption of Mount St. Helens,  October 1
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Image shows billowing clouds of steam and smoke emanating from the ground
November 30, 2000

Mount St Helens Phreatic Eruption

Phreatic eruption at the summit of Mount St. Helens, Washington. Credit: D.A. Swanson, USGS