@mountsthelensarchive: Oct. 19, 1980 | Eruption #6’s End Mount St. Helens erupts Saturday, Oct. 18, at 12:35 p.m. and again at 2:28 p.m. Less than an hour later at 3:20 p.m., a spotter plane sees a new lava dome in the crater. By Sunday, Oct. 19, ABC News’ Tom Schell reports, it’s 155 feet high. Portland State University’s Leonard Palmer: “It’s faster growing. It’s much steeper. It looks like a mushroom with overhang base.” Scientists aren’t calling the eruption over. The University of Washington’s Steve Walter: “The hunch is that it may not be over.” USGS geologist Susan Russell-Robinson: “We can expect almost anything from Mount St. Helens. We just don’t know.” Yet, the 2:28 p.m. blast on Saturday would be the last of the October eruptions, ending the last major explosive activity of the 1980s. Lava was added to the dome in late December, and dome building continued through 1986. By 1990, the composite dome that grew from it rose about 1,150 feet above the crater floor. Sources: ABC News, Oct. 19, 1980 (Tom Schell); The Sunday Oregonian, Oct. 19, 1980; The Oregonian, Oct. 20, 1980; USGS Professional Paper 1250; Eruptions of Mount St. Helens: Past, Present, and Future, USGS.

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Monday 19 October 2026 23:54:57 GMT