Hikers in Sicily have been warned to stay away from Mount Etna after a sizable eruption sent tourists fleeing from the 11,165ft peak. Videos posted to social media show people running from a large grey cloud, which quickly emerged from the active volcano at around 11.30am on Monday, June 2.

A massive eruption at Mt. Etna forced tourists to flee the volcano on Monday after a plume of high temperature gases, ash and rock “several kilometers high” billowed into the air above them, Italian authorities said.

Mount Etna is Europe’s largest active volcano and has erupted at least once per year for the last several years.