A visit to Mount St. Helens

The May 18, 1980, eruption displaced roughly 2.6 km[sup 3] of rock and devastated more than 500 km[sup 2] of forest, mostly to the north of the mountain. Trees within 10--15 km of the mountain peak were burned and uprooted. Beyond that, high winds and flying debris created a blowdown zone. Up to 150 m of rock and ice covered some areas. Accumulations of ash were measured as much as 330 km from the volcano. Mud flows choked nearby rivers and streams. Two years later, the US Congress established the 44,000-hectare Mount St. Helens National Volcanic Monument. The Act essentially directed the USDA Forest Service to allow the area to recover naturally. The paper reviews what changes the ecosystem has been going through since the eruption and the lessons learned that suggest some new resource management techniques.