Summary of Events
http://volcanoes.usgs.gov/volcanoes/st_helens/st_helens_geo_hist_99.html
1980 Eruption FAQs
http://volcanoes.usgs.gov/volcanoes/st_helens/st_helens_sub_page_78.html
Volcanic eruptions of 1980 at Mount St. Helens; the first 100 days
1982, Foxworthy, B. L.; Hill, Mary
USGS Professional Paper: 1249
Download .pdf file @ http://pubs.er.usgs.gov/publication/pp1249
The 1980 eruptions of Mount St. Helens, Washington
1981, Edited by Lipman, Peter W.; Mullineaux, Donal Ray
USGS Professional Paper: 1250, 844 pages.
Download single large .pdf file (250 MB) @ http://pubs.er.usgs.gov/publication/pp1250
Mount St. Helens – From the 1980 Eruption to 2000
U.S. Geological Survey Fact Sheet 036-00
http://pubs.usgs.gov/fs/2000/fs036-00/
30 Cool Facts about Mount St. Helens
By Carolyn Driedger, Liz Westby, Lisa Faust, Peter Frenzen, Jeanne Bennett, and Michael Clynne
U.S. Geological Survey General Information Product 103
Mount St. Helens, 1980 to now—what’s going on?
Dzurisin, Daniel; Driedger, Carolyn L.
USGS Fact Sheet: 2013-2014