Legacy of Mount St. Helens 1980 eruption still defies perfect solution
Aerial view of Spirit Lake (center) looking north from above the crater of Mount St. Helens. The lake's outlet to the west (left) was blocked by the 1980 landslide, which required a new engineered outlet to maintain the lake at a safe level. A tunnel was drilled through a bedrock ridge on west side of lake in 1984-1985. Glacier covered Mount Rainier in distance. USGS photo by M. Logan, 2005.