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[[Image:Pyroclastic_flow.jpg|thumb|300px|Pyroclastic flow sweeps down the side of Mayon Volcano, Philippines,  during an explosive eruption on 15 September 1984. Note the ground-hugging cloud of ash (lower left) that is billowing from the pyroclastic flow and the eruption column rising from the top of the volcano.]]A hot, fast-moving and high-density mixture of fine and coarse particles and gas formed during explosive [[eruption]]s or from the collapse of a [[lava dome]]. (Gardner, et.al., 1995)<ref>[http://vulcan.wr.usgs.gov/Glossary/volcano_terminology.html Glossary of Volcano and Related Terminology]</ref>

[[Image:Pyroclastic_flow.jpg|thumb|300px|Pyroclastic flow sweeps down the side of Mayon Volcano, Philippines,  during an explosive eruption on 15 September 1984. Note the ground-hugging cloud of ash (lower left) that is billowing from the pyroclastic flow and the eruption column rising from the top of the volcano.]]A hot, fast-moving and high-density mixture of fine and coarse particles and gas formed during explosive [[eruption]]s or from the collapse of a [[lava dome]]. (Gardner, et.al., 1995)<ref name="gloss">[http://vulcan.wr.usgs.gov/Glossary/volcano_terminology.html Glossary of Volcano and Related Terminology]</ref>

Lateral flowage of a turbulent mixture of hot gases and unsorted [[pyroclastic material]] (volcanic fragments, [[crystal]]s, [[ash]], [[pumice]], and [[glass]] shards) that can move at speed (50 to 100 miles an hour). The term also can refer to the deposit so formed. (Foxworthy and Hill, 1982)<ref>[http://vulcan.wr.usgs.gov/Glossary/volcano_terminology.html Glossary of Volcano and Related Terminology]</ref>

Lateral flowage of a turbulent mixture of hot gases and unsorted [[pyroclastic material]] (volcanic fragments, [[crystal]]s, [[ash]], [[pumice]], and [[glass]] shards) that can move at speed (50 to 100 miles an hour). The term also can refer to the deposit so formed. (Foxworthy and Hill, 1982)<ref name="gloss" />

A hot (300-800 degrees C (570-1470 degrees F)), dry, fast-moving (10 to more than 100 meters per second (20 to more than 200 miles per hour)) and high-density mixture of [[ash]], [[pumice]], [[rock]] fragments, and gas formed during explosive eruptions or from the collapse of a lava dome. Moves away from a [[volcano]] at high speeds. <ref>[http://vulcan.wr.usgs.gov/Glossary/volcano_terminology.html Glossary of Volcano and Related Terminology]</ref>

A hot (300-800 degrees C (570-1470 degrees F)), dry, fast-moving (10 to more than 100 meters per second (20 to more than 200 miles per hour)) and high-density mixture of [[ash]], [[pumice]], [[rock]] fragments, and gas formed during explosive eruptions or from the collapse of a lava dome. Moves away from a [[volcano]] at high speeds. <ref name="gloss" />

Pyroclastic flows are arguably the most dangerous of all volcanic flows, due to their fast speed and destructive power.

Pyroclastic flows are arguably the most dangerous of all volcanic flows, due to their fast speed and destructive power.