lahar

A lahar is a fast-moving flow of volcanic mud, ash, water, and rocks that occurs when volcanic material from an eruption mixes with rain, melted snow, or ice on a volcano’s slopes. These flows behave like wet cement, carrying debris and capable of devastating anything in their path. Lahars can travel many miles down valleys, reaching communities and infrastructure, posing serious hazards to lives and property. They are a significant volcanic hazard because they can happen during or long after an eruption, especially during heavy rainfall or rapid snow melt on active volcanoes.