What is Pyroclastic Flow?

A pyroclastic flow is a fast-moving current of hot gas and rock that rushes down the side of a volcano. Pyroclastic flows are extremely dangerous because they can move at speeds up to 700 kilometers per hour (430 miles per hour) and reach temperatures of 1,000 degrees Celsius (1,800 degrees Fahrenheit).

Pyroclastic flows usually occur during explosive eruptions when the pressure of rising magma causes the expulsion of gases and rocks from the volcano. The magma itself can also fragment into small pieces, which become part of the flow. Pyroclastic flows typically travel down the slope of the volcano until they reach flatter ground where they spread out.

Lahars, or mudflows, are another type of dangerous flow that can occur during volcanic eruptions. Lahars form when water from rain or melting snow mixes with loose ash and debris on the slopes of a volcano. This mixture can quickly turn into a fast-moving river of mud that can bury houses and cars. Lahars typically occur during rainy weather or when snow melts quickly on the slopes of a volcano.

Volcanic eruptions are unpredictable and dangerous events that can have devastating consequences for people living nearby. It is important to be aware of the dangers associated with volcanoes and to know what to do if an eruption occurs.