Mount Etna, the rambunctious volcano on the Italian island of Sicily, grumbled back to life on Monday, spewing hot ash and lava in a pyroclastic flow, the nation’s volcano monitoring body said. There was no immediate report of any risk to the local population, which is accustomed to Etna’s frequent eruptions, or to air travel.
The volcano department, which is run by Italy’s National Institute of Geophysics and Vulcanology, noted on Monday “explosions of increasing intensity” that it said were “almost continuous.”
By noon local time, INGV Vulcani said in a social media post that the “explosive activity from the Southeast Crater has become a lava fountain,” and infrared images posted by the group showed the flow of lava down the mountain’s face.
Video shared earlier on the institute’s Facebook page showed a massive plume of smoke and ash rising into the clear blue sky.
Mount Etna is considered the most active volcano in Europe, and the most active stratovolcano in the world. A stratovolcano — what many people think of when they hear the word volcano — is the conical type, often with a central crater, that is formed by layer upon layer of lava from repeated eruptions over the millennia.
INGVvulcani/Dr. Dario Stelitano 
Etna had a significant eruption just over a year ago, when it treated watchers to rare ring-like clouds puffed out by its crater, known as vortex bubbles. (See the video at the top of this article.)
Etna has erupted at least once every year for the past several years, sometimes covering nearby towns in a layer of volcanic dust, but causing no major problems otherwise.