A lava flow is a stream of molten rock that erupts from a volcano during an eruption. This molten rock, known as lava, can vary in temperature and composition, affecting how it moves and solidifies. Lava flows can travel down the sides of a volcano, spreading out over the landscape and creating new landforms as they cool and harden. The speed and distance of a lava flow depend on factors like its viscosity and the slope of the terrain. Pahoehoe and aa are two common types of lava flows, with pahoehoe being smooth and ropy, while aa is rough and jagged. Both types can pose hazards to nearby communities and ecosystems.