Typed caption not available. Note: Slide numbers 43 - 50 were taken at 19:01 and show the pyroclastic flow as it advances northward. Skamania County, Washington. July 22, 1980. Slide number 51 was taken at 19:02. Slide numbers 52 - 55 were taken at 19:03. Slide numbers 56 - 57 were taken at 19:04. Slide numbers 58 and 59 were taken at 19:04 and 19:05. Slide numbers 60 - 62 are views of the eruption and were taken at 19:06. Slide no. 52, msh_vjw00052_ct, is highlighted in this photo record. Slide no. 52 typed caption: View of eruption at 19:03, the plume develops a mushroom-like head while the elutriate cloud from the pyroclastic flow billows up through the cloud layer. Skamania County, Washington. (Photo by J. Vallance) Additional note: Mount St. Helens. List of color transparencies of the July 22, 1980 eruption. The following slides (1-114) 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 began at 17:14, 18:30 and 19:02 PDT.