@misc{indiciaedbef140e7909,
  title = {The initial giant umbrella cloud of the May 18th, 1980, explosive eruption of Mount St. Helens},
  author = {R. S. J. Sparks and J.G. Moore and C.J. Rice},
  year = {1986},
  url = {https://pubs.usgs.gov/publication/70015660},
  note = {Source identifier: 70015660}
}