This 7x-speed footage captures a massive pyroclastic flow racing down Indonesia’s Mount Semeru as the volcano unleashed a powerful eruption. | AccuWeather

When a volcano erupts, pyroclastic flows are often the biggest danger to anyone nearby. These fast-flowing currents of rock, ash and hot gas are extremely difficult to study, so researchers created their own. Read the related Nature Geoscience paper here: https://go.nature.com/2Im1bYs | Nature Portfolio

PYROCLASTIC FLOW A pyroclastic flow is a fast-moving current of extremely hot gas, volcanic ash, and rock fragments that rushes down the slopes of a volcano during explosive eruptions. These flows can reach speeds of over 320 km/h and temperatures exceeding 1,000 °C, making them one of the most dangerous volcanic hazards. Unlike lava flows, pyroclastic flows can travel great distances, destroy everything in their path, and cause widespread devastation due to their speed, heat, and suffocating as