Mount St. Helens, a prominent volcano in the Pacific Northwest, is widely recognized for its dramatic 1980 eruption. This event profoundly reshaped the mountain, giving it a distinctive appearance. Its current form stands as a testament to the powerful geological forces unleashed over four decades ago.
Before the Eruption
Prior to May 18, 1980, Mount St. Helens presented a very different image. It was celebrated for its nearly perfect conical shape, often earning it the nickname “Mount Fuji of America.” This symmetrical peak rose gracefully, reaching an elevation of 9,677 feet, making it the fifth-highest peak in Washington at the time. Its upper slopes were typically covered in snow and ice, featuring eleven named glaciers. Its picturesque appearance made it a popular destination.
The 1980 Transformation
The 1980 eruption fundamentally altered Mount St. Helens’ structure. Triggered by a magnitude 5.1 earthquake, a massive landslide removed the mountain’s entire north face. The lateral blast unleashed hot gases and debris, creating a large, horseshoe-shaped crater. The eruption reduced the mountain’s height by approximately 1,300 feet, lowering its summit to 8,363 feet. The aftermath left a changed landscape, contrasting with the verdant forests that once surrounded the volcano.
Its Current Distinctive Features
Today, Mount St. Helens is characterized by its prominent, north-facing horseshoe-shaped crater, which measures about 1.2 to 1.8 miles wide and approximately 2,084 feet deep. Within this crater, a large lava dome has formed and continued to grow. This dome, initially developing between 1980 and 1987, saw further significant growth during a renewed eruptive period from 2004 to 2008, doubling its volume. The dome’s surface appears rugged and is composed of crumbled rock, slowly expanding into a broader, more symmetrical shape as its steep sides erode.
Another feature inside the crater is Crater Glacier, which formed after the 1980 eruption. This glacier encircles the lava dome in a horseshoe shape, growing due to heavy snowfall, avalanches, and shade from the crater walls. The glacier is a mix of ice and rock (about 60% ice and 40% rock), giving its surface a dark appearance from rockfall and ash. It has an average thickness of 328 feet, reaching up to 656 feet in some areas. Its debris cover helps insulate the ice, contributing to its persistence.
Ongoing Changes
Mount St. Helens remains a dynamic landscape, continuously evolving. The lava dome within the crater continues to undergo changes, although significant growth ceased in early 2008. The Crater Glacier continues to expand, though at a slower rate than its initial growth. This glacier is gradually filling parts of the crater, showing how the mountain’s internal processes continue to shape its appearance.
Beyond the crater, the surrounding blast zone is undergoing a gradual process of natural revegetation and ecological recovery. Plants and wildlife have slowly returned, creating a mosaic of recovering habitats. This ongoing ecological succession, alongside the geological changes within the crater, illustrates that Mount St. Helens is a living laboratory, constantly transforming.