Ash emissions from Semeru volcano reach 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 21:10 UTC on November 1, 2025. The advisory was issued by the Darwin VAAC at 21:30 UTC.

According to the VAAC advisory, volcanic ash was reported at altitudes up to FL140, or approximately 4 300 m (14 100 feet), moving toward the southwest at 9 km/h (5.6 mph). The ash was not identifiable on satellite imagery due to meteorological cloud cover. Ground-based reports indicate intermittent, discrete eruptions are ongoing. The current Aviation Color Code is Orange.

The Smithsonian/USGS Weekly Volcanic Activity Report confirms continuing activity at Semeru during the previous week, with daily eruptive events. White-and-gray or gray ash plumes rose 400–900 m above the summit and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1–4), with public warnings to stay at least 3 km from the summit in all directions, 8 km to the southeast, and to avoid specified drainages due to lahar and pyroclastic flow hazards.

Semeru is an active stratovolcano on Java, Indonesia. Known for frequent explosive eruptions, it poses hazards including ashfall, pyroclastic flows, lava flows, and lahars. The closest city at risk is Lumajang, located about 30 km (19 miles) to the southeast, with smaller communities closer to the volcano also facing potential danger.