Columbia subject headings:
Saint Helens, Mount (Wash.)--Eruption, 1980--Congresses.
Harvard subject headings:
Ecology--Washington (State)--Saint Helens, Mount, Region--Congresses.
Natural history--Washington (State)--Saint Helens, Mount, Region--Congresses.
Saint Helens, Mount (Wash.)--Eruption, 1980--Congresses.
Saint Helens, Mount (Wash.)--Eruption, 1980--Environmental aspects--Congresses.
Volcanic ash, tuff, etc.--Environmental aspects--Washington (State)--Saint Helens, Mount, Region--Congresses.
Princeton subject headings:
Saint Helens, Mount (Wash.)--Eruption, 1980--Congresses.