Volcanic ash from Semeru volcano observed at 4 300 m (14 100 feet) a.s.l., Indonesia

Volcanic ash from Semeru in Indonesia was observed at 4 300 m (14 100 feet) above sea level at 21:00 UTC on November 2, 2025. The advisory was issued by the Darwin VAAC at 21:30 UTC on November 2, 2025.

Ash was reported at surface to flight level 140 (approximately 4 300 m or 14 100 feet) and moving east at 9 km/h (5.6 mph). The ash cloud was not identifiable on satellite imagery due to meteorological cloud cover. The current Aviation Color Code is Orange. The reported ash height and movement are based on ground reports and model guidance, with intermittent discrete eruptions ongoing.

According to the latest Smithsonian / USGS Weekly Volcanic Activity Report, Semeru experienced daily eruptive events during September 24–30, 2025. White-and-gray or gray ash plumes rose 400–900 m (1 300–3 000 feet) above the summit and drifted in multiple directions. The Alert Level remained at 2, and the public was advised to remain at least 3 km (1.9 miles) from the summit in all directions, and further away along selective drainages.

Semeru is a stratovolcano located in East Java, Indonesia. It is known for frequent explosive eruptions producing ash plumes, lava flows, pyroclastic flows, and lahars. Its ongoing activity poses hazards to nearby settlements such as the town of Lumajang, as well as to aviation due to ash emissions. The primary volcano-related risks include ashfall, volcanic flows, and potential disruption of river drainages leading to secondary lahars.