Ash cloud 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 09:00 UTC on October 24, 2025. The advisory was issued by the Darwin VAAC at 09:30 UTC.

Ash was reported at flight level 140, which is equivalent to approximately 4 300 m (14 100 feet) above sea level. The ash plume was observed moving southwest at a speed of 19 km/h (12 mph). The current Aviation Color Code is Orange. Satellite imagery did not clearly identify ash due to meteorological cloud cover; the reported ash height and movement were based on ground observations and model guidance.

According to recent reports by the Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG), activity at Semeru continued in late September 2025, with daily ash plumes rising 400–900 m above the summit and drifting in multiple directions. The public was warned to stay at least 3 km away from the summit in all directions and 8 km to the southeast due to ongoing hazards.

Semeru is an active stratovolcano located in East Java, Indonesia. Known hazards include ashfall, pyroclastic flows, lava flows, and lahars. Settlements such as Lumajang and villages near the southern slopes are within risk zones, especially in valley areas that can channel volcanic flows. Ongoing activity can pose significant risks to local populations and aviation in the region.