Mt St Helens is a stratovolcano situated on the Cascade Arc in Washington State, USA
On the 8th of May 1980 a 5.1 on the Richter scale earthquake rumbled under the north side of Mount St Helens.
Moments later an explosion blasts away the north side of the volcano resulting in the biggest landslide ever recorded.
The lateral landslide exposed the magma in the neck of the volcano. The magma melted the snow and glaciers instantly, which resulted in a cataclysmic explosion.
The resulting blast directed a pyroclastic flow of hot gasses, ash and pumice
at a speed of 670 miles per hour, at a temperature of 700 degrees centigrade, northwards in a fan shape.
An ash cloud accelerated 15 miles up into the atmosphere in less than 10 minutes.
Prior to the eruption the volcano was a fine example of a symmetrical snow and glacier covered cone with an elevation of 9,677 feet.
The eruption left a crater one mile wide and two miles long, the volcano lost one cubic mile of rock representing 12% of the mountains volume and was reduced in height by 1,370 feet, giving it a post eruption elevation of 8,307 feet.
Its an awesome drive through the recovering wilderness to the foot of this powerful volcano.
Enjoy the video