The most recent event to dramatically shape the geology and landscape of the refuge occurred just a few decades ago. On May 18, 1980, Mount St. Helens, located 150 miles southwest of the refuge, erupted violently, sending a cloud of volcanic ash over eastern Washington and turning day into night. A heavy layer of powdery ash settled on the refuge, varying in depth from 1 inch on the southern areas to 2 inches near the north. The ash flattened vegetation and suffocated many terrestrial insects, creating food shortages for other wildlife. Over the years, the ash layer has eroded and been incorporated into the soil but is still evident throughout the refuge.
April 17, 2014
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