Ash cloud from Semeru volcano reaches 4 300 m (14 100 feet) a.s.l., Indonesia

Volcanic ash from Semeru in Indonesia was observed at an altitude of 4 300 m (14 100 feet) above sea level at 09:40 UTC on October 11, 2025. The advisory was issued by the Darwin VAAC at 10:00 UTC on the same day.

Ash clouds associated with this event were reported at surface level up to flight level 140, or approximately 4 300 m (14 100 feet). The ash was moving southwest at approximately 19 km/h (12 mph). The ash was not identifiable on recent satellite imagery due to meteorological cloud cover; information on cloud height and movement was instead derived from ground reports and model guidance. The current Aviation Color Code is Orange.

According to the latest summaries from the Global Volcanism Program, daily eruptive activity at Semeru continued during late September 2025. Daily 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 public was advised to remain at least 3 km (1.9 miles) from the summit in all directions and up to 8 km (5 miles) to the southeast, as well as to avoid areas near river drainages due to lahar, avalanche, and pyroclastic flow hazards.

Semeru is a large stratovolcano in East Java, Indonesia and is the highest volcano on the island. Known hazards include ashfall, pyroclastic flows, lava flows, and lahars. The nearby town of Lumajang, along with several villages, is located within 20 km (12 miles) of the volcano and is at risk from these volcanic hazards.