Volcanoes Deadly Pyroclastic Flows Surf on Air to Achieve Super Speed | NOVA
Lava might be the most iconic fixture of an erupting volcano, but its sluggish ooze pales in comparison to the blast of a pyroclastic flowa roiling river of gas, ash, and rock that can hurtle down a mountainside at hundreds of miles per hour. These fast-moving floods, with searing temperatures up to 1,800 degrees Fahrenheit,