Two hundred and thirty square miles levels in moments... Five hundred and forty million tons of ash and volcanic rock exploded twelve miles high... One cubic mile of earth blasted from the crest of one of the world's most beautiful snow-capped domes... Captured in rare and spectacular aerial photography and survivor's own words and pictures, witness the terrifying fury of the worst volcanic disaster in American history. Fifty-seven people were killed or are still missing as for more than nine hours a vigorous plume of ash erupted, eventually rising 15 miles above sea level, that moved eastward at an average speed of 60 miles per hour. The mountain lost 1,300 feet of altitude in the eruption of May 18, 1980 as from the centre of the plume larva flowed down the left flank of the volcano. Then, behold the miraculous natural recovery of the land and the new and awesome beauty of the volcano today, two decades since its devastating eruption. Guided by Mount St. Helens National Volcanic Monument geologists, learn the prehistoric secrets of the mountain.