Brief History of Mt. St. Helens

Indians on the Cowlitz River watching an eruption of Mount St. Helens, as painted by Canadian artist Paul Kane following a visit to the volcano in 1847 (Photograph courtesy of the Royal Ontario Museum).

Mt. St. Helens used to look like a very beautiful land formation; often referred to as “the Mount Fuji of America.” 

This however, was before the massive eruption of 1980. The volcano had been formed during 4 eruptive stages. The first started about 275,000 years ago. An older volcano had been there, but it didn’t really damage anything or go anywhere except to the base of the volcano. This composite volcano tended to erupt very violently, as many composite volcanoes do. Part of the Ring of Fire, Native Americans named this mountain as “ ‘Louwaia- Clough,’ or ‘smoking mountain.’ ” 

In the past, the volcano had been studied, and evidence of prior eruptions was evident. The volcano had had periods where it had erupted many times, then went into a dormant type of period until the next eruptive period. During the 1980 eruption, pressure was building, which many officials worried about. So, they moved people out of the vicinity. Then, part of the volcano collapsed, simultaneously releasing pressure and letting magma flow out. This release still triggered a minor eruption, where debris was thrown up and lava spewed out. Later, as a second eruption, heat killed many trees, and also made the once dense forest bare. The near-supersonic blast accompanied pyroclastic flows, which covered about 6 square miles. 57 humans were killed during the eruption, along with a blast that covered about 230 square miles. So much thermal energy was released that the amount of trees blown down and killed would have been enough to build 300,000 2-bedroom homes. The landslide stretched about 23 square miles, so the entire devastation and damage was incredibly big. 

* Photos: USGS