http://www.newsweek.com/what-are-lahars-guatemalas-mt-fuego-may-cause-volcanic-mudflows-experts-warn-957121

Sunday's eruption of the Fuego volcano in Guatemala has ended, at least for now, after killing at least 25 people, according to the country's disaster response agency. But even if the volcano remains quiet, residents of the area aren't necessarily safe quite yet.

Guatemala's national agency monitoring earthquakes, volcanos and the weather, has warned that in the wake of the eruption, areas around the volcano may be at risk of what scientists call lahars, which are sort of like very fast mudflows, but filled with rock particles released by the eruption.