When Is Mount St. Helens Going to Erupt Again?

While it is not yet possible to predict volcanic eruptions decades in advance, the U.S. Geological Survey’s Cascades Volcano Observatory continually monitors Mount St. Helens to gather data for more accurate short-term predictive models. According to “Future Eruptions at Mount St. Helens,” this volcano is the most likely to erupt in the Cascade Mountains of Washington again in the coming decades.

Mount St. Helens erupted on Sunday, May 18, 1980, causing an earthquake that measured 5.1 on the Richter scale and collapsed the volcano’s north face. The resulting avalanche, hot gases and hot lava, pushed by a lateral blast, leveled 150 square miles of forest, houses and towns.

Because Mount St. Helens has formed a deep crater, USGS research suggests it’s unlikely that a subsequent eruption will cause the same massive avalanches and lateral blast. The Cascades Volcano Observatory offers current data on Mount St. Helens on its website, as well as multimedia galleries and links to published research.

In 1982, Congress set aside 110,000 acres to create the Mount St. Helens National Volcanic Monument in order to study the long-term effects of the eruption and to preserve the landscape. During the summer, U.S. Forest Service staff offer visitors a wide range of educational activities from short walks to presentations in the monument’s amphitheatre.