A Pyroclastic Flow is a violent super-hot ( as much as 1075*C) avalanche of speeding volcanic rocks, ash, gasses and other volcanic debris. A Pyroclastic flow can flatten entire cities . Soufriere Hills Volcano is a stratovolcano on the island of Montserrat in the Carribbean, West Indies known for it massive pyroclastic flows. It is composed primarily of stiff andesitic lavas that have a high gas and silica content making them extremely explosive. It has an elevation of 3,002 feet (915 m) and began erupting on July 19, 1995. This image shows one of the most destructive eruptions known to man--A Pyroclastic Flow. Photograph taken at night in 2002.