Europe’s most active volcano, Mount Etna, erupted on Monday morning, producing an enormous ash cloud “several kilometers high.” The volcano is located in Sicily, Italy, near the city of Catania.

The eruption began at 11:24 a.m. local time, according to reports. Italy’s National Institute of Geophysics and Volcanology warned of “almost continuous” explosions that were of “increasing intensity” caused by a section of Etna’s southeast crater crumbling. Approximately half an hour after it began, the organization reported that the vulnerable area had become a “lava fountain” due to the volcanic explosions.