Mount St. Helens

The famous Spirit Lake surrounding Mount St. Helens is also a result of violent activity. The lake formed when mudflows form the volcano blocked the headwaters of a fork of the Toutle River and the lake was raised over 60feet by mudflows.
             Prior to 1980, after over one hundred years of lying dormant, St. Helens had the opportunity to recuperate from its previous eruptions and develop its beautiful shape, rising approximately 3000 meters above sea level. (Sanders 2002) The landscape surrounding the mountain consisted of dense, temperate and coniferous rain forests. .
             Large areas had been partially modified by timber harvest activity and sparse alpine vegetation occurred at high elevations. Lakes and streams were also common to the area. However, by 1949 endless miles of roads covered the previously solitude mountain. By 1975 there were few roadless areas for hikers and wildlife and most of the trails had been converted to logging road (Williams 1988). According to the U.S Forest Service, timber harvesting had been "quite extensive, primarily on the south and east sides" (Williams 1988:32). The timber industry claimed that clearcutting was an economic necessity essential for providing timber and jobs. Clearcutting moved up Mount. St. Helen streams and efforts to replant the timberline clearcuts failed and once the vegetation was destroyed, the pumice became a desert, and few plants were able to grow. Only the north side of the mountain prior to the 1980 eruption remained in a semi-natural state, although fisheries were damaged by dams and erosion from logging (Williams 1988).
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             The Cascade Mountains, St. Helen's being one of them, represent a volcanic arc that is created where the Juan the Fuca tectonic plate is moving eastward and subsiding beneath North America. The plate originated as magma, through rifts in the Juan de Fuca Ridge. The Juan de Fuca Ridge is the remaining northern segment of a larger oceanic feature called the Farallon Ridge.