Global Volcanism Program | Image GVP-02902
Pumice clasts from the 18 May 1980 eruption form the pumice plain immediately north of Mount St. Helens, shown in this 23 May photo. Pumiceous pyroclastic flows on 18 May traveled 8 km from the crater, as far as Spirit Lake. A geologist can be seen holding a large, light-weight block of pumice. Pumiceous pyroclastic flows were also erupted on 25 May, 12 June, 22 July, 7 August, and 16-18 October 1980.
Photo by Dan Miller, 1980 (U.S. Geological Survey).
This image is made available as a Public Domain Work, but proper attribution is appreciated.