Ash emissions at Lewotobi volcano reach 3.7 km (12 000 feet) a.s.l., Indonesia

An eruption at Lewotobi volcano, Indonesia, on June 20, 2025, generated a volcanic ash cloud observed moving north-northwest. According to a volcanic ash advisory issued at 17:40 UTC, the ash was detected at 3.7 km (12 000 feet) above sea level, based on satellite imagery and ground reports. The summit of Lewotobi stands at 1 703 m (5 587 feet), situating the ash plume approximately 2 000 m (6 600 feet) above the summit.

The advisory indicated that the volcanic ash cloud was partially identifiable on RGB satellite imagery at 17:20 UTC and was forecast to continue moving north-northwest at a speed of 10 knots. The current Aviation Color Code is Red, indicating an ongoing eruption with significant ash emission. Forecasts projected the ash cloud to persist in the region for at least 18 hours. The CVGHM reported ongoing emissions from the volcano.

According to the Smithsonian’s Global Volcanism Program weekly report issued for the period ending May 27, 2025, Lewotobi Laki-laki experienced a decrease in eruptive activity following a significant event on May 18. During the following week, seismic indicators suggested reduced surface activity and magmatic recharge at depth. Eruptive events in late May produced ash plumes and crater-filling lava, and by May 25, the Alert Level was lowered to 3, with a public exclusion zone of 6 km from the summit. White steam-and-gas plumes were reported in the days following.

Lewotobi is a complex stratovolcano system comprising the twin Lewotobi Laki-laki and Lewotobi Perempuan cones. The main hazards associated with Lewotobi are ashfall, pyroclastic flows, and lava flows, which could present risks to communities nearby, such as the town of Lewo and other settlements on Flores Island. Continued eruptions can impact air travel and pose health risks to residents through ashfall and volcanic gases.