Eruption at Lewotobi volcano sends ash up to 9 450 m (31 000 feet) a.s.l., Indonesia

Volcanic ash from Lewotobi volcano in Indonesia was observed at an altitude of 9 450 m (31 000 feet) above sea level at 00:35 UTC on October 15, 2025. The advisory was issued by the Darwin VAAC at 01:56 UTC on October 15, 2025.

According to the VAAC advisory, volcanic ash was observed at various altitudes, with the primary cloud near the summit and extending up to flight level 180 (approximately 5 500 m or 18 000 feet) and additional cloud to flight level 220 (approximately 6 700 m or 22 000 feet). The highest level of ash reached was flight level 310 (approximately 9 450 m or 31 000 feet), reported by CVGHM. The ash was moving west-northwest at approximately 19 km/h (12 mph). Satellite imagery from Himawari-8 and information from CVGHM supported these observations and forecasts. The current Aviation Color Code is Red.

According to the Smithsonian / USGS Weekly Volcanic Activity Report, during late September 2025, the Lewotobi Laki-laki cone produced daily white-and-gray or gray ash plumes rising as high as 2 000 m (6 600 feet) above the summit. Ash drifted north, northwest, west, and southwest. A nearby airport, 60 km (37 miles) west of the volcano, closed temporarily due to ash, causing flight cancellations. As of September 29, 2025, the Alert Level was lowered to 3 (on a scale of 1-4), and people were advised to remain at least 6 km (3.7 miles) from the center.

Lewotobi consists of two stratovolcanoes, Lewotobi Laki-laki and Lewotobi Perempuan, located in eastern Flores Island, Indonesia. Both volcanoes pose hazards from explosive eruptions, ashfall, pyroclastic flows, and lahars. Several villages and the town of Larantuka, approximately 50 km (31 miles) northeast, are the principal settlements at risk from large explosive events.