The most common and serious types of volcanic hazards are flowing lava, falling ash, glowing avalanches and moving mud and debris. The exact hazard level varies depending on the type of volcano erupting. Additional hazards include the emission of hazardous gases and eruption clouds, which are dangerous to planes and helicopters.Continue Reading
Eruption columns and clouds are the products of explosive volcanoes, with clouds reaching as high as 12 miles. The 1980 eruption of Mount St. Helens in Washington state spread debris from the eruption columns throughout an area of 22,000 square miles.
Dangerous gases, such as fluorine, hydrogen, carbon dioxide, hydrogen sulfide and sulfur dioxide, can cause acid rain, which is dangerous to humans, livestock and agriculture. Lava flows, characterized by fast-moving magma emerging from deep within the Earth, can affect areas within a couple of square miles of the volcano. Kilauea Volcano in Hawaii destroyed at least 200 homes with flowing lava during its 1983 eruption.
Glowing avalanches, technically referred to as pyroclastic flows, occur when the pressure of eruption creates a landslide of magma, ash, rock and gases. Regular landslides, such as those experienced around Washington's Mount Rainier, disrupt the surrounding land. Similarly, a mudflow known as a lahar is one of the deadliest volcano hazards.Learn more about Volcanoes