Slides of the July 22, 1980 eruption of Mount St. Helens. Skamania County, Washington. 1980.

These slides of the July 22, 1980 eruption of Mount St. Helens were taken by Jim Vallance, who was in a U.S. Forest Service fixed wing aircraft and by Mike Doukas, Harry Glicken, and Rick Hoblitt who were in a U.S. Geological Survey helicopter. There were three major eruptive pulses on July 22, 1980. They begin at 17:14, 18:30 and 19:02 PDT. Slides no. 5 through 25 were taken between 18:25:20 and 18:26:30 This sequence was taken while moving counter-clockwise from the north to the west flank of Mount St. Helens at a distance of about 7 miles and while changing elevation from about 10,000 to 12,000 feet. Approximately 3 seconds after slide no. 20. Skamania County, Washington. (Photo by J. Vallance, USGS) View of eruption at 18:27. Base [...]