Volcanic ash from Lewotobi volcano observed at 6 700 m (22 000 feet) a.s.l., Indonesia

Volcanic ash from Lewotobi volcano in Indonesia was observed at altitudes up to 6 700 m (22 000 feet) above sea level at 09:40 UTC on October 15, 2025. The advisory was issued by the Darwin VAAC at 10:00 UTC.

According to the VAAC advisory, ash was detected at two distinct altitudes: from the surface up to 4 600 m (15 000 feet) moving toward the north-northwest, and near the summit up to 6 700 m (22 000 feet) moving north, as observed in satellite imagery and supported by model guidance. The current Aviation Color Code is Red. The advisory notes that the ash at lower altitudes is expected to dissipate within 6 hours, while ash near the summit is expected to dissipate within 12–18 hours.

The Smithsonian / USGS Weekly Volcanic Activity Report (24–30 September 2025) notes that Lewotobi Laki-laki experienced daily white-and-gray or gray ash plumes rising as high as 2 000 m (6 600 feet) above the summit, drifting in several directions. Seismic activity was dominated by low-frequency earthquakes, non-harmonic tremor, and eruptive signals. The volcano’s Alert Level was recently lowered to 3 (on a scale of 1–4).

Lewotobi consists of a twin stratovolcano complex on Flores Island, Indonesia. The main hazards from Lewotobi include explosive eruptions producing ash plumes, pyroclastic flows, and lava flows. Ashfall may impact nearby settlements including the towns of Larantuka and surrounding villages within a 20 km (12 miles) radius, and past activity has disrupted regional air traffic. Continued monitoring is essential to assess risks to communities and aviation in the area.