what is mudflow on a volcano
Description [edit]. Lahar is a Javanese word that describes volcanic mudflows or debris flows. Lahars have the consistency, viscosity and approximate density of wet concrete: fluid when moving, solid at rest.Lahars can be huge.ahars have several possible causes: 1  Snow and glaciers can be melted by lava or pyroclastic flows during an eruption. 2  Lava flows out of open vents and can mix with wet soil and mud on the slope of the volcano making a very viscous, high energy lahar. 3  A flood caused by a glacier, lake breakout, or heavy rainfall can release a lahar, also called ....