May 18, 1980. For most of America, the day dawned bright and beautiful. Most of its citizens were aware of the drama unfolding on the west coast—the imminent eruption of Mount Saint Helen’s had been all over the news for the past several weeks. Geologists had been recording and reporting an uptick in seismic activity in the area and the news journalists were diligently announcing impending doom. However, no-one could warn the country of the extent of the catastrophe to come from the initial and subsequent explosions as the beautiful mountain spewed its steam and ash into the once pristine atmosphere and landscape surrounding it.
Nearly everyone in The United States and Canada were affected by the resulting devastation. More than two-thirds of a cubic mile (2.8 km3) of rock was ejected and pulverized to ash, which blasted up to 16 miles (26 km) into the atmosphere. The ash-cloud stem was 10 miles (16 km) wide, and the mushroom top was 40 miles (64 km) wide and 15 miles (24 km) high. Winds in the atmosphere dispersed the ash eastward at 60 mph (100 km/h), blanketing 11 states and several Canadian provinces with dust. Some towns were engulfed in complete darkness at midday. (Snelling). The ash affected air travel and ground deliveries for several weeks. Those directly affected by the ash suffered respiratory issues and crops that year yielded poorly under the cloud.
Mount Saint Helen’s isn’t the largest volcano in the Cascade Range, nor was the eruption at 0831, May 18, 1980 the largest in recorded history. (Snelling, Francis and Hennigan). Yet it has become the most studied eruption in history. (Thomas) The lessons we learned from this event has helped save countless lives over the next three and a half decades by helping scientists predict future eruptions all over the world. Geologists vastly improved their ability to predict eruptions, safely evacuating tens of thousands of Filipino people before Pinatubo erupted in 1991 (Snelling, Francis and Hennigan).
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Mount St Helen’s was predicted to likely to erupt in the twentieth century by Dwight Crandall and Don Millineaux in 1978 (SDSU). Two years later, the first seismographs were put into operation on the mountain. (Bagely)
Eleven of the eighteen very high threat volcanoes are in Washington, Oregon, or California, where explosive and often snow- and ice-covered volcanoes can project ash or lahar (debris flow) hazards long distances to densely populated and highly developed areas. These include Mount St. Helen’s, Mount Rainier, Mount Hood, Three Sisters, Newberry, Mount Baker, Glacier Peak and Crater Lake (in Washington and Oregon), and Mount Shasta, Lassen and Long Valley (in California). The threat ranking is not a list of which volcano will erupt next. Rather, it indicates how severe the impacts might be from future eruptions at any given volcano. (USGS) Geologists are monitoring this entire area constantly to (hopefully) help reduce loss of life in the event any of these volcanoes should erupt.
The USGS, in its summary of its new Lahar fact sheet notes this. These devastating mud flows are far more destructive than floodwaters. They sweep trees, structures and even boulders along their downhill routes leaving catastrophic destruction in their paths by wet sandblasting and rapidly eroding even solid rock. The debris picked up, in turn, contributes to the destructive force until the entire mess comes to rest. The Lahar fact sheet published by the CVO states ““ (USGS) With millions of Americans living in the areas potentially affected, it isn’t any wonder our geologists spend so many resources and time studying the Cascade Range.
Rivers and other natural channels redistribute disrupted material such as magma, rock, debris and volcanic ash.” (USGS) Initially, this debris choked out the fish and other water-dependent lifeforms with the mud and toxic minerals concentration. These contaminated waters were most concentrated in and around the Colombian Estuary but lakes and streams only affected by ash residue experienced changes as well, albeit to a lesser degree. (Lee, USGS) Although ecological recovery has been occurring over the past thirty-five years or so, Green River, the largest tributary of the North Fork Toutle River, and “” (American Rivers)
Scientists do not think Mount Saint Helen’s will remain silent for long. “” (USGS) The David A. Johnston Cascades Volcano Observatory (CVO) is part of the USGS Volcano Hazards Program and the scientists stationed there monitor restless volcanoes. They also develop new tools and measuring devices to accurately gauge the activity they are observing.
The Cascade Range of volcanoes is more complicated than initially thought. After 35 years of study, scientists are still trying to determine what caused the build up of magma in its chambers. (Akpan). If we’ve learned anything since the 1980 eruption, it must be that we’ve only begun to tap the realization of our ignorance.
It was fortunate that the seismographs were installed before Mount St. Helen’s erupted so we could gather so much last minute data. Although geologists were only able to gain about three months data prior to the eruption, they were able to garner so much information, they are still learning from the data collected nearly forty years later. The theories and hypothesis generated from studying Mount Saint Helen’s and other Cascade Range Volcanoes is being applied world wide and used to generate timely evacuations in other countries to prevent major loss of life.
