Details remain fuzzy, but as these images clearly show, the effects were horrific, particularly as there was little warning of what was about to transpire. People, cars, buildings, and anything standing in the path of these flows, moving at speeds of around 80 kilometers (50 miles) per hour, were blasted away.
Anyone caught up in the flows would have experienced internal temperatures ranging from 200 to 700°C (390-1,300°F). Much like the victims of Pompeii, they would have experienced extremely severe burns, extreme heat shock and organ failure within mere moments, and perished.
As these satellite images show, entire villages are now nothing but muddy cinders. At the same time, the danger isn’t over. Another explosive event at Fuego could cause similar flows, but plenty of volcanologists are keen to point out that that’s not the only danger here.
When the material from a pyroclastic flow settles, it’s mostly in the form of an unconsolidated sheet of ash. It’s rainy season there right now, so inundation of this ash is likely. When wet enough, and when on a slope – say, in a valley – it can quickly mobilize as a mudflow. Named “lahars”, these are fast-moving, concrete-like mudslides, and they also take people by surprise.
Sure, pyroclastic flows can be deadly: they’ve killed 45,000 people in the 20th century alone, which accounts for about 49 percent of all volcanic deaths.
Lahars shouldn’t be underestimated though. The most horrific example comes courtesy of Colombia’s 1985 Nevado del Ruiz disaster, when pyroclastic flows were mobilized by melting glacial water. The resulting colossal mudflows killed as many as 23,000 people while they slept in their beds.
These satellite images, then, will help volcanologists work out which areas are most at risk. Good luck to all involved.