What is Pyroclastic flow?
[[File:Pyroclastic flows at Mayon Volcano.jpg|thumb|right|250px|Pyroclastic flows going down [[Mayon Volcano]], [[Philippines]], in 1984.]] A '''pyroclastic flow,''' pronounced pie-roh-class-tick, (also known as a '''pyroclastic density current''') is a flow of hot [[volcanic gas]] and [[tephra]], during a [[volcanic eruption]]. A cloud forms over the [[:wikt:current|current]] of hot [[rock (geology)|rock]]. This boiling column of superheated gas, [[sand]], tephra, [[obsidian]], and [[pumice]] can reach soaring temperatures of {{convert|1000|C|F|sigfig=2}} and its average speed ranges from {{convert|100|km/h|m/s mph|-1|abbr=on}} to {{convert|700|km/h|m/s mph|-1|abbr=on}}. They are extremely dangerous and can be deadly. A person cannot outrun a pyroclastic flow. [[Category:Volcanology]] {{science-stub}}