Pyroclastic Flow on the Eastern Flank of Etna – many people close to the eruption
Catania, June 2, 2025 – 11:45 AM
During Etna’s 14th eruptive phase — considered a mild paroxysm — a pyroclastic flow unexpectedly occurred at 11:24 AM CEST. It originated from the northeastern flank of the Southeast Crater and surged through the Valle del Bove, partially reaching the Valle del Leone.
The flow was likely triggered by the collapse of a lava flow or a section of the crater flank due to the ongoing activity. Pyroclastic flows on Etna often result from lava breaking through the cone’s sides, causing structural collapse.
Preliminary assessments suggest this was one of the largest pyroclastic flows ever observed at Etna. The INGV later stated the flow likely did not extend beyond the Valle del Leone’s boundary — crucial, as this ridge (Serra delle Concazze) is frequented by hikers.
Simultaneously, strombolian activity intensified into a lava fountain. It remains unclear whether a sudden pressure build-up caused the collapse or whether the collapse itself triggered explosive decompression of magma. Volcanic ash was detected at 6,400 m altitude, prompting a red alert from VAAC Toulouse.
Recent monitoring indicated magma accumulation beneath the Southeast Crater in a north-south trending zone. Previous eruptions had already revealed new vents on the northwest side, suggesting structural weakness.
This incident highlights the unpredictability and danger of volcanoes — and raises concerns about tourist safety. While access to Stromboli is strictly limited even during normal activity, visitors are transported by cable car and bus to within 300 m of Etna’s active craters — despite significantly higher eruption levels. A glaring safety gap that demands attention.