A flow of pyroclastic material mixed with water. A lahar is often produced when a snow-capped volcano erupts and hot pyroclastics melt a large amount of snow or ice.

A flowing mixture of water and rock debris that forms on the slopes of a volcano, sometimes referred to as debris flow or mudflow. The term comes from Indonesia.

A volcanic debris flow.

an Indonesian word that refers to a rapidly flowing mixture of rock debris and water (other than normal water flows) from a volcano. When they overflow their channels, lahars can destroy, erode or bury obstacles in their path. There are various kinds of lahar. A debris flow lahar (the type expected in the current situation) flows like a slurry and contains large amounts of sediment (more than 60 per cent of volume) of varying size (from small particles to boulders). A hyperconcentrated flow lahar contains less sediment, mainly of sand-sized or smaller particles, and flows more like water. Lahars are produced by most eruptions on Ruapehu but also by dam or rim collapse (eg 1953), landslides and heavy rain. Some very recent pre-historic lahars have been very much larger then any seen in historic times.

A very rapid type of downslope mass movement that involving mudflows from volcanic ash.

A mudflow composed of volcanic materials such as ash.

mudflow of unconsolidated volcanic ash, dust, breccia, and boulders that occurs when pyroclastic or lava deposits mix with rain or the water of a lake, river, or melting glacier.

An Indonesian term for a debris flow containing angular clasts of volcanic material. For the purposes of this report, a lahar is any type of sedimentwater mixture originating on or from the volcano. Most lahars move rapidly down the slopes of a volcano as channelized flows and deliver large amounts of sediment to the rivers and streams that drain the volcano. The flow velocity of some lahars may be as high as 20 to 40 meters per second and sediment concentrations of greater than 750,000 parts per million are not uncommon. Large volume lahars can travel great distances if they have an appreciable clay content (greater than 3 to 5 percent), remain confined to a stream channel, and do not significantly gain sediment while losing water. Thus, they may affect areas many tens to hundreds of kilometers downstream from a volcano.

pyroclastic material deposited at the base of a volcano

A mudflow associated with volcanic eruptions when volcanic ash mixes with water.

An Indonesian term for a debris flow or mudflow originating on a volcano.

an avalanche of volcanic water and mud down the slopes of a volcano

a bit like a plate of porridge spilled on a sloping surface

a catastrophic mudflow or debris flow consisting of a mixture of rock, ash, water, snow, and pyroclastic materials that originates on the slopes of a volcano

a massive flow of water and rock down the side of a volcano, according to the United States Geological Survey Web site

a mass of volcanic debris and water flowing rapidly from a volcano

a mixture of rock, mud, and water that flows down from a volcano (or occasionally other mountains), typically along a river valley

a mixture of volcanic ash, rock, debris, and water that can travel quickly down the slopes of a volcano

a mudflow that occurs in volcanic materials

a mudslide generated from the flanks of a volcano

a special type of debris flow that originates from the slopes of a volcano Debris flow crossing a road

Mudflows formed by the mixing of volcanic particles and water.

Mudflow comprised of mainly volcanic debris.

a water-saturated mixture of mud and debris that flows rapidly downslope; often formed when hot volcanic material falls on snow and ice or when rain saturates loose volcanic debris.

A torrential flow of water-saturated volcanic debris down the slope of a volcano in response to gravity. A type of mudflow. Usage of lahar. For a larger discussion on lahars, click here.

A lahar is a mudflow or debris flow originating on a volcano. Jökulhlaups (see above) often become lahars when they incorporate the rock debris that lies within their path.

A type of mudflow that originates on the slopes of volcanoes when volcanic ash and debris becomes saturated with water and flows rapidly downslope.

A mixture of water and rock debris that forms on the slopes of a volcano. Also known as a mudflow or debris flow. The term comes from Indonesia.

(pronounced LAH-hahr)a mudflow composed of volcanic ash and water that occurs in the wake of a volcanic eruption.

a massive flood of water mixed with mud and vegetation, triggered by volcanic activity. Can be from the sudden draining of a crater lake, or from volcanic heat suddenly melting snow and ice that previously capped the volcano.

a water-based landslide or mudflow of cooled and solidified chunks of pyroclastic material on the flank of a volcano.

A volcanic ‘mudflow'. Lahars are mixtures of ash and rock fragments in water that flow with the consistency of wet cement and may be hot.

A thick slurry formed when volcanic ash and debris mix with water, either in rivers or from rain or melting snow and ice on the flank of a volcano.

A lahar (also called a mudflow or debris flow) is a moving mixture of rock, water, and other debris that falls down the slopes of a volcano and/or a river valley. Lahar is an Indonesian word

A landslide or mudflow of pyroclastic material on the flank of a volcano. Also the name of the deposit it produces. Here is a view of a lahar deposit from Mount St. Helen along the Toutle River.

An Indonesian term for rapidly flowing mixtures of volcanic materials and water.

A flow of rock debris, ash and mud that occurs on many volcanoes particularly during eruptions. Large lahars can be very destructive and can be a major cause of death.

mud flow of water and volcanic material (volcanic ash, volcanic blocks (lava bombs), etc); deposits from such are also called a lahar.

mud flow of ash and water on the sides of a volcano

A Lahar is a type of natural disaster closely related to a volcanic eruption, and involves a large amount of material, including mud, rock, and ash sliding down the side of the volcano at a rapid pace. These flows can destroy entire towns in seconds and kill thousands of people. The Tangiwai disaster is an excellent example.

is a mudflow or debris flow originating on a volcano. Jokulhlaups (see above) often become lahars when they incorporate the rock debris that lies within their path. Lateral Moraine A moraine formed at the side of a glacier. Piles of loose unsorted rocks along the side margins of the glacier. The rocks may be pushed there by the moving ice or dumped from the glacier's rounded surface.

A a torrential mudflow of water mixed with volcanic debris.

landslide or mudflow of pyroclastic material on the flank of a volcano; deposit produced by such a landslide. Lahars are described as wet if they are mixed with water derived from heavy rains, escaping from a crater lake or produced by melting snow. Dry lahars may result from tremors of a cone or by accumulating material becoming unstable on a steep slope. If the material retains much heat, they are termed hot lahars. AGI

A lahar is a type of mudflow composed of pyroclastic material and water that flows down from a volcano, typically along a river valley. The term 'lahar' originated in Indonesia.