Volcanic ash from Lewotobi volcano observed at 3 700 m (12 100 feet) a.s.l., Indonesia

Volcanic ash from Lewotobi volcano in Indonesia was observed at 3 700 m (12 100 feet) above sea level at 12:00 UTC on October 9, 2025. The advisory was issued by the Darwin VAAC at 12:25 UTC on October 9, 2025.

The ash cloud was reported at surface to flight level 120, which corresponds to approximately 3 700 m (12 100 feet). The observation was based on ground reports, satellite imagery from Himawari-9, and model data. The current Aviation Color Code is Red. The ash was reported moving southwest at a speed of 9 km/h (6 mph). Satellite detection was not possible at the time of the report due to meteorological cloud cover.

According to the Smithsonian / USGS Weekly Volcanic Activity Report for September 24–30, 2025, daily white-and-gray ash plumes from Lewotobi Laki-laki rose up to 2 000 m (6 600 feet) above the summit and drifted in multiple directions. Ashfall temporarily closed the Fransiskus Xaverius Seda Airport, located 60 km (37 miles) west, and caused flight cancellations. At 15:00 UTC on September 29, 2025, the Alert Level was lowered to 3, with a recommendation to remain at least 6 km (3.7 miles) from the volcano’s center.

Lewotobi is a complex stratovolcano system on Flores Island, Indonesia, consisting of twin volcanoes Lewotobi Laki-laki and Lewotobi Perempuan. The main hazards include ashfall, pyroclastic flows, and lahars, which can impact nearby communities and infrastructure, especially in areas within a 10 km (6.2 miles) radius of the volcano. The city of Larantuka and surrounding settlements are the primary populations at risk during eruptions.