This is why volcanic clouds move so fast

The dangers of volcanoes don't end at hot magma and falling rocks — you also have to worry about the plumes of ash, smoke, and toxic gases that are just as deadly, but reach a lot farther. Thanks to new research, scientists might be able to better understand how these volcanic clouds work, and how we can minimize their damage.

Clouds of volcanic debris, known as "pyroclastic density currents," have long been a mystery because they move much faster than they should be able to, National Geographic explained. They stick to ground level and seem to have an unnatural momentum that allows them to race downhill, on level surfaces, and even uphill. But a new study published Monday in the journal Nature Geoscience revealed that volcanic gases are able to spread at abnormal speeds thanks to a cushion of air that reduces the amount of friction they encounter in their path.

Using volcanic debris left behind by a volcanic eruption 2,000 years ago in New Zealand, researchers studied the way the pyroclastic flow moved, and were able to model the movement on computers. This data led them to the realization that air trapped between the toxic particles in the pyroclastic current drifted to the bottom of the clouds, buffering the current from any rough surfaces it might pass over. It's similar to the way an air hockey table works: The puck gains speed because of the layer of air that lifts it from the table's surface.

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Although the data needs to be refined, it can be a tool in predicting where future eruptions' volcanic gases and ash might end up. That information, in turn, can be used to save the lives of the 800 million people who live within 60 miles of active volcanoes around the world.

Read more about this study at National Geographic.