The eruption of Mount St. Helens on May 18, 1980, caused the destruction of 27 bridges, over 200 homes and 4.7 billion boards of timber. In addition, 15 miles of railway and 185 miles of highway were damaged or destroyed. Fifty-seven people also lost their lives during the eruption, and another four deaths occurred as an indirect result of the eruption.
In the immediate area, immeasurable damage was caused to the forest area from falling ash, lahars, flooding and mudslides. In the direct blast zone closest to the eruption site, everything within an eight-mile radius was completely obliterated. Aside from the destruction of buildings, cars and forestry, thousands of animals were killed.
When Mount St. Helens erupted, the ash column rose 12 miles high. The ash settled over Washington, Oregon and Idaho, and it even reached Colorado, Minnesota and Oklahoma. The settlement of ash caused the destruction of acres of crops, and thousands of dollars were spent on clean-up efforts. In all, the eruption of Mount St. Helens cost over one billion dollars in damage.
The eruption of Mount St. Helens also had many secondary effects. For example, local tourism was affected by the eruption, and unemployment increased significantly in the area surrounding Mount St. Helens.