Mount St. Helens - 1982

An aerial view from 1982 shows the massive debris avalanche deposit and Pumice Plain directly north of Mount St. Helens’ fractured crater. Following the cataclysmic May 18, 1980 eruption, this unstable landscape filled the upper North Fork Toutle River valley to an average depth of 150 feet, creating a decades-long sediment management challenge for the Portland District, U.S. Army Corps of Engineers. (USACE photo)