How Mount St. Helens Eruption Changed the World

3. Communities learned that a day-long eruption could affect rivers decades later
The 1980 eruption sent immense amounts of mud, water, and debris downstream, overtopping banks and flooding low-lying valleys. Sediment clogged channels in the Toutle, Cowlitz, and, eventually, Columbia Rivers. There was so much new sediment in the Columbia River that the riverbed rose by nearly 30 feet, halting ship traffic and severely impacting the local economy. Today, those rivers continue to transport sediment downstream at rates tens of times greater than before the eruption. This enormous amount of extra sediment continues to pose challenges for flood protection and fisheries today. The lesson was clear, eruptions change river systems even decades later.

4. Scientists discovered that nature recovers quickly, building new and thriving habitats
Before 1980, scientists had limited experience observing the direct effects of explosive eruptions on plants and animals. Many presumed that all life would perish when the ash, steam, and volcanic debris scorched the landscape. People believed it would take several generations of plants, insects, and animals to rebuild nutrient-rich soils and repopulate the landscape. However, since not all ecosystems were uniformly devastated, over the years, a new, complex mosaic of habitats emerged after the eruption. The diversity of life at Mount St. Helens today exceeds that of the pre-eruption landscape. The same long-term ecological studies finely tuned at Mount St. Helens are now used to assess volcanically disturbed regions worldwide.

5. Congress preserved a unique volcanic landscape to explore and learn from
People were fascinated by Mount St. Helens following the 1980 eruption. To accommodate the interest of tourists and researchers to visit and study this newly transformed landscape, in 1982 Congress set aside 110,000 acres around the volcano for preservation. They created the Mount St. Helens National Volcanic Monument and directed the U.S. Forest Service to protect the new landscape and its plant, animal, and cultural resources. Now, visitors can traverse trails or climb the volcano, and researchers can study the geologic forces and the evolving ecology in the protected area.

6. Scientists and public officials have become better prepared to face volcanic threats
After Mount St. Helens erupted, residents of the Pacific Northwest wanted to know what the volcano would do next. Scientists, land managers, and public-safety officials coordinated their efforts and a new era of volcano crisis management was born. Now, scientists and public officials meet regularly to assess potential hazards and practice emergency responses and share information with the public. Today’s emergency managers draw a direct line from lessons learned at Mount St. Helens to current volcanic hazard planning efforts at many other volcanoes.

7. A new generation of volcanologists emerged around the world
After Mount St. Helens’ eruption, worldwide interest in volcanism blossomed. Scientists and eager students sought to understand volcanoes, improve monitoring and warning systems, assess volcanic hazards, and communicate with at-risk populations. Since 1980, hundreds of volcanologists from around the world have come to study Mount St. Helens. The relationships built with international colleagues, the advances in monitoring, and the skills accumulated have made it possible for U.S. scientists to aid with eruption responses worldwide. The USGS Volcano Disaster Assistance Program team has responded to more than 70 volcanic crises worldwide and strengthened response capacity in 12 nations. The lessons learned at Mount St. Helens help address concerns at other reawakening volcanoes, both in terms of science and hazard mitigation.

8. Scientists gained insights into the geologic history of Mount St. Helens
In 1980, scientists became acquainted with one of nature’s most massive and destructive volcanic processes—the debris avalanche. Until then, relatively few people had witnessed one, but on May 18, 1980, startled onlookers saw, and some even photographed, the collapse and debris avalanche that demolished the north slope of Mount St. Helens. Observations that day allowed scientists to better link eruptive processes with their geologic deposits. Geologic mapping and improved methods for determining the ages of past eruptions yielded some surprises at Mount St. Helens. Although much of the present mountain grew remarkably fast during the last 4,000 years, it sits atop older volcanic deposits that erupted as long ago as 270,000 years. With every eruption, rocks from lava flows, pyroclastic flows, lahars, and ash-rich deposits accumulated, one upon another, to remake the volcano.

9. Scientists have a better grasp of Cascades volcano hazards and eruption frequency
The 1980 Mount St. Helens eruption inspired a new generation of research on Cascades volcanoes throughout Washington, Oregon, and California. Scientists documented their eruption histories, identifying specific hazards and areas that are at risk during future eruptions. Some Cascades volcanoes were discovered to erupt more frequently than previously thought. We now know that there is about a one in 100 chance that an eruption will occur from a Cascade volcano in any given year, with Mount St. Helens being the most likely culprit.

10. A technological revolution sparked new ways to monitor volcanoes and provide hazard warnings
Before 1980, only one seismometer was deployed within 30 miles of Mount St. Helens to detect earthquakes and scientists’ ability to detect rising magma and make eruption forecasts was limited. Since 1980, volcano monitoring has evolved from a few strategically placed instruments and occasional field observations to broad integrated networks of sensors that detect various indications of volcanic activity. Scientists can now remotely measure and monitor earthquake activity, ground deformation, temperature variations, magma movement, and volcanic gas composition and emission rates in real time. These advancements allow scientists to provide early warnings that give emergency officials the time they need to make life-saving decisions.