From Seattle: Mt Saint Helen Tour｜United States

The image of Mount Saint Helen's will always be associated with the United States and the rest of the world. Life changed in an instant during the events leading up to the 1980 eruption, and the mountaintop's geography was permanently changed. Today, you may explore this distinct volcano and all the flora and wildlife that contribute to the remarkable reforestation initiative.
The Johnston Ridge Observatory is open seasonally and is located on Johnston Ridge in the center of the 1980 blast zone approximately 8 km (5 mi) north of the Mount St. Helens summit. The Ridge was named in honor of David Johnston, the USGS volcanologist who was on duty at the USGS Coldwater II observation point during the May 18, 1980 eruption. He was one of 57 people who lost their lives in the eruption. The Observatory building houses seismic, deformation, and other monitoring equipment that relays data to the USGS Cascades Volcano Observatory for analysis.