Spirit Lake (Washington)

Spirit Lake is a mountain lake in southwestern Washington state at the northern base of Mount St. Helens that was dramatically changed by the 18 May 1980 eruption.

The shoreline and surface are notable for extensive floating log mats and standing dead trees left by the debris avalanche and blast; the lake and surrounding area are now part of the Mount St. Helens National Volcanic Monument.

Before 1980 the lake was a clear, forested mountain lake; the eruption buried the old shoreline, raised the lake level with debris and logs, and created a long-term ecological and geomorphological research site.

The lake lies within Gifford Pinchot National Forest and the Mount St. Helens National Volcanic Monument in southwestern Washington, with viewpoints and visitor facilities on the volcano’s northern side.

• 1980 eruption: The volcano eruption of 18 May 1980 catastrophically altered the lake - a massive landslide and blast filled the basin with logs and debris and raised the water level.
• Viewing and access: Key viewing points for the lake and the volcanic north face include the Mount St. Helens National Volcanic Monument overlooks such as Johnston Ridge Observatory and nearby designated viewpoints.