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

Volcanic ash from Lewotobi in Indonesia was observed at an altitude of 6 700 m (22 000 feet) above sea level at 06:40 UTC on October 15, 2025. The advisory was issued by the Darwin VAAC at 07:00 UTC.

According to the advisory, volcanic ash was detected by satellite (Himawari-8) and CVGHM. Ash was observed moving north-northwest from the summit at flight level 150 (approximately 4 600 m or 15 000 feet) and at flight level 220 (approximately 6 700 m or 22 000 feet) near the summit in light winds. The current Aviation Color Code is Red. Ash at lower levels was forecast to move north-northwest at about 28 km/h (17 mph), with dissipation of the lower cloud expected within 6 hours and the higher altitude cloud anticipated to dissipate in 12–18 hours.

The Smithsonian / USGS Weekly Volcanic Activity Report for September 24–30, 2025, notes that Lewotobi Laki-laki produced daily white-and-gray or gray ash plumes rising as high as 2 000 m (6 600 feet) above the summit, drifting north, north-northwest, west, and southwest. On September 26-27, nearby Fransiskus Xaverius Seda Airport (60 km or 37 miles west) was closed due to ash, affecting flights. Seismic and ground measurements indicated ongoing activity, with the Alert Level reduced to 3 on September 29, and the public advised to remain at least 6 km (3.7 miles) from the center.

Lewotobi consists of twin stratovolcanoes, Lewotobi Laki-laki and Lewotobi Perempuan, located on Flores Island, Indonesia. The volcano poses hazards including ashfall, lava flows, pyroclastic flows, and lahars. Local settlements at risk include nearby towns such as Boru and several villages within 20 km (12 miles), as well as broader regional impacts on air travel when ash emissions rise to high altitudes.