Flexi Says: Pyroclastic flows typically comes from composite volcanos. Composite volcanoes are also called stratovolcanoes. This is because they are formed by alternating layers (strata) of magma and ash. The magma that creates composite volcanoes tends to be thick. The steep sides form because the lava cannot flow too far from the vent. The thick magma may also create explosive, or pyroclastic, eruptions.
