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Mount St. Helens or Louwala-Clough is an active stratovolcano located in Skamania County, it is known as Lawetlat'la to the indigenous Cowlitz people.

Will scientists ever be able to accurately predict volcanic eruptions? That’s what Naked Science asks as it examines how volcanologists around the world study gas emissions, ground deformation, temperature changes and seismic and electromagnetic data to try and tell when volcanoes will erupt.

Seeking clues that could help prevent the next terrifying volcanic eruption we revisit the disaster of Mount St. Helens that occurred in May 1980, in the state of Washington, United States.

The major eruption was preceded by a two month series of earthquakes and steam venting episodes, caused by an injection of magma at shallow depth below the volcano that created a huge bulge and a fracture system on the mountain's north slope. An earthquake on 18th May 1980 caused the entire weakened north face to slide away, creating the largest landslide ever recorded. This suddenly exposed the partly molten, gas and steam rich rock in the volcano to lower pressures. The rock responded by exploding a hot mix of lava and pulverized older rock toward Spirit Lake so fast that it overtook the avalanching north face.

The eruption column rose 80,000 feet into the atmosphere and deposited ash over 11 U.S. states. At the same time, snow, ice and several entire glaciers on the volcano melted, forming a series of large volcanic mudslides. Approximately fifty seven people were killed directly, and hundreds of square miles were reduced to wasteland.

Clip taken from our documentary “Volcano Alert”.

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