What is a pyroclastic flow?

A pyroclastic flow comes is created from a volcano that blasts out part of volcanic mountain into the sky.  It is a mixture of very hot volcanic rock, gases, ash and other trace elements that travels at hundred of miles per hour down the side of the volcanic mountain.  If you are in the way of a pyroclastic flow there is no escape and your life is in immense danger because of their temperature and mobility.  It is best to stay away from active volcanoes that could have a chance of developing a pyroclastic flow.  Pyroclastic flows have also been known to travel as far as 30 kilometers from the volcano.