lahars
Hot volcanic debris-flows
Lahars are volcanic mudflows—fast-moving slurries of water, ash, rock, and debris that sweep down mountain slopes during or after eruptions.
They follow river valleys and can travel great distances, burying everything in their path under thick mud.
Lahars form when volcanic material mixes with water from melting snow, heavy rain, or crater lakes.
Among the most destructive volcanic hazards, they can devastate communities far from the eruption itself.
Fast-moving liquefied earth
- volcanicOf fiery mountain origin
- debrisScattered broken fragments
- pyroclasticHot eruption debris
- stratovolcanoLayered cone-shaped volcanic mountain
deposit · channel · valley · sediment · eruption · Mount Pinatubo · volcanic ash · Mount Rainier
Frozen mass becoming water
- rainfallWater falling from clouds
- snowmeltLiquefied winter precipitation
- floodwaterExcess from swollen rivers
- saturationState of complete permeation
drainage basin · river channel · dam failure · jökulhlaup · streamflow · watershed · monsoon · typhoon
Severe widespread destruction
- burialPlacing deceased underground
- floodingOverwhelming water accumulation
- casualtiesThose killed or wounded
- infrastructureBasic physical systems
bridges · roads · villages · inundation · displacement · evacuation · warning systems · destruction
Concealed detection lines
- early warningAlert before event occurs
- evacuation routesPlanned emergency exit paths
- USGSFederal earth science agency
- alert systemsNotification mechanisms for emergencies
detection · sirens · real-time monitoring · rain gauges · webcams · telemetry · emergency broadcast · preparedness
mudflow
Fast-moving liquefied earth
- volcanicOf fiery mountain origin
- debrisScattered broken fragments
- pyroclasticHot eruption debris
stratovolcano · deposit · channel · valley · sediment · eruption · Mount Pinatubo · volcanic ash · Mount Rainier · debris flow
glacial melt
Frozen mass becoming water
- rainfallWater falling from clouds
- snowmeltLiquefied winter precipitation
- floodwaterExcess from swollen rivers
saturation · drainage basin · river channel · dam failure · jökulhlaup · streamflow · watershed · monsoon · typhoon · cyclone
devastation
Severe widespread destruction
- burialPlacing deceased underground
- floodingOverwhelming water accumulation
- casualtiesThose killed or wounded
infrastructure · bridges · roads · villages · inundation · displacement · evacuation · warning systems · destruction · engulfment
tripwires
Concealed detection lines
- early warningAlert before event occurs
- evacuation routesPlanned emergency exit paths
- USGSFederal earth science agency
alert systems · detection · sirens · real-time monitoring · rain gauges · webcams · telemetry · emergency broadcast · preparedness · risk assessment
laharslava
Erupted liquid stone
lava flows · pyroclastic flows · magma · molten rock · volcanic bombs