Spirit Lake (Washington)

Spirit Lake
(February 2005)
Location	Mount St. Helens National Volcanic Monument, Skamania County, Washington, USA
Coordinates	46°16′23″N 122°08′06″W
Primary inflows	Precipitation, streams
Primary outflows	Drainage tunnel
Basin countries	United States
Surface elevation	3,406 feet (1,038 m) (3,198 ft (975 m) before May 18, 1980)

Spirit Lake is a lake north of Mount St. Helens in Washington State. The lake was a popular tourist destination for many years until the 1980 eruption of Mount St. Helens. With the eruption and resulting megatsunami, thousands of trees were torn from the surrounding hillside after lake water was displaced 800 feet up the hillside. Lahar and pyroclastic flow deposits from the eruption then blocked the North Fork Toutle River valley at its outlet, raising the surface elevation of the lake by over 200 ft (60 m). The newly raised lake, once it reappeared, was also 10 percent smaller and much shallower.

After the eruption, Spirit Lake contained highly toxic water with volcanic gases seeping up from the lake bed. A month after the eruption, the bacteria-carrying water was devoid of oxygen. Scientists predicted that the lake would not recover quickly, but the reemergence of phytoplankton starting in 1983 began to restore oxygen levels. Amphibians such as frogs and salamanders recolonized the lake, and fish (reintroduced by fishermen) thrived.

The water level of Spirit Lake is maintained at about 3,406 feet (1,038 meters) by draining water through a gravity-feed tunnel completed in 1985. The 2,500-feet (762 meters) -long tunnel was cut through Harrys Ridge to South Coldwater Creek. Had the lake level not been stabilized, its mud dam created by the 1980 eruption probably would have been breached, possibly causing catastrophic floods in the Toutle River.

Before the eruption of Mount St. Helens, there were four camps on the shore of Spirit Lake: a Boy Scout camp, a Girl Scout camp, a YMCA camp, and another for the general public. There were also a number of lodges catering to visitors, including Spirit Lake Lodge and Mt. St. Helens Lodge; the latter was inhabited by Harry R. Truman, who became one of the volcano's victims.

Gallery

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  Spirit Lake prior to 1980

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  Spirit Lake filled with debris from the eruption. October 4, 1980

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  Logs covering Spirit Lake, 2009

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  Spirit Lake

References

• Dale, Virginia H.; Swanson, Frederick J.; Crisafulli, Charles M. (2005). Dale, Virginia H.; Swanson, Frederick J.; Crisafulli, Charles M.. eds. Ecological Responses to the 1980 Eruption of Mount St. Helens. doi:10.1007/0-387-28150-9. ISBN 978-0-387-23868-5. 
• USGS Cascades Volcano Observatory: Spirit Lake
• [1] describes the tunnel that maintains the lake water level.