David Jackson is based on real-life scientist David Johnston. He died in the same way and uttering the same final words into his radio before the blast of Mt. St. Helens hit him, "Vancouver! Vancouver! This is it!" The rest of the depiction of him, however, was decried by Johnston's family and his colleagues at the USGS for misrepresenting his character, so much so that Johnston's family threatened to sue the filmmakers for libel.
Central Oregon's Mt. Bachelor was used for the pre-eruption scene of Mt. St. Helens. Mt. Bachelor and Mt. St. Helens, both volcanoes, are on the Cascade Mountain range.
First Hollywood soundtrack of the italian prog-rock group Goblin (Massimo Morante, Claudio Simonetti, Fabio Pignatelli, Agostino Marangolo and Antonio Marangolo)
The film takes place from March 20 to May 18, 1980.
The location for the surface of Mt. St. Helens was a local garbage dump in Bend, Oregon.