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Spirit Lake

From Oregon Hikers Field Guide

Spirit Lake and Mt. Adams from Harrys Ridge (bobcat)
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Spirit Lake is a body of water that was birthed and has been radically altered by volcanic activity for its entire existence. The lake was originally formed by the damming of two creeks by volcanic lahars issuing from Mount Saint Helens about 4,000 years ago. The 1980 eruption and resulting landslide displaced the lake waters in a tidal wave over 250 yards high and reduced the lake's depth due to infill by volcanic debris. However, Spirit Lake's surface area increased by about 1,000 acres to 2,200 acres. The lake essentially became a vast log pond for the thousands of full-grown conifers blown into the depression by the blast.

The waters of the new Spirit Lake were contained by a soft and vulnerable dam of pyroclastic material: there was no longer a natural outlet. In 1985, engineers constructed a 2,600-yard overflow tunnel under Harrys Ridge to relieve pressure on the dam which, if breached, could have caused catastrophic flooding.

Initially, lake waters were completely deprived of oxygen after the eruption and all life vanished. Within a few years, however, the natural regimen reestablished itself, and the lake has returned rather rapidly to pre-eruption health. Trout were illegally introduced by fishermen and have thrived.

Before the 1980 eruption, Spirit Lake was a popular destination for fishermen and campers. There were several campgrounds, both public and private, around the lake as well as some rustic lodges. Harmony Falls was a picturesque waterfall that tumbled near one of these lodges: both are now gone. The caretaker of the Mt. St. Helens Lodge was 83-year-old Harry Truman, who refused to leave in the days building up to the eruption and became a media celebrity. When the volcano blew, Harry and his 16 cats were buried under 150 feet of searing pyroclastic material.



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