Today marks 46 years since the eruption of Mount St. Helens, a disaster that forever changed the Pacific Northwest. On May 18, 1980, the volcano erupted with tremendous force, killing 57 people and sending ash across Washington and much of the western United States. In Central Washington, ash turned daytime into darkness. In Yakima, several inches blanketed the city, shutting down businesses, grounding travel, and forcing residents to wear masks just to step outside.