The lava was actually a fast moving cloud of hot gas and ash, called a pyroclastic flow
Pressure from magma and dissolved gases built up in the magma chamber in the volcano, building up a bulge on the north side, until the mountain gave way, and erupted
Pressure from magma and dissolved gases built up in the magma chamber in the volcano, building up a bulge on the north side, until the mountain gave way, and erupted
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There was no bubbling lava. Helens was a ash blast - the side bulged and then a landslide occurred and the lost weight of material released the pressure inside and it blew hundreds of tonnes of ash into the air and down the side as intensely hot pyroclastic flows. http://www.google.com/search?q=pyroclast…