Mount St. Helens erupted in southwestern Washington May 18, 1980.After the eruption fragmented rock, ash and debris choked nearby rivers, threatening local communities downstream. (Corps of Engineers photo) [When mountains move, humans can only watch and figure out how to work with the changes.]

Mount St. Helens erupted in southwestern Washington May 18, 1980.After the eruption fragmented rock, ash and debris choked nearby rivers, threatening local communities downstream. (Corps of Engineers photo)

Mount St. Helens erupted in southwestern Washington May 18, 1980.After the eruption fragmented rock, ash and debris choked nearby rivers, threatening local communities downstream. (Corps of Engineers photo)