During late September 2008 we visited Mount St Helens to characterize the roundness of pumice erupted and transported in pyroclastic flows erupted in the May 18, 1980 eruptions. See Dufek and Manga (2008) for the background of this project and the predictions we were seeking to test and extend.
Ameeta Patel, Michael Manga, Joe Dufek and Max Rudolph
North face.
Spirit Lake with Mt Adams in the background
Pumice-rich flow near the top of the middle pyroclastic flow sequence.
Waterfall
Frogs seem to like pumice too.