Ash cloud from Semeru volcano reaches 4.3 km (14 100 feet) a.s.l., Indonesia

An ash cloud from Semeru volcano in Indonesia was reported following eruptive activity last observed at 09:57 UTC on June 16, 2025. The Darwin VAAC issued an advisory confirming that at 11:10 UTC, an ash cloud reached an altitude of 4.3 km (14 100 feet) above sea level and was moving toward the north-northwest at 10 knots.

Meteorological clouds prevented visual detection of volcanic ash in the latest satellite imagery, though regular ground reports indicated intermittent discrete emissions were ongoing. The altitude of the ash was determined based on a combination of satellite data, ground reports, and model guidance. The current Aviation Color Code is Orange. Forecasts suggest the ash cloud could persist at similar altitudes and continue drifting in the forecasted direction over the next 18 hours.

According to the Smithsonian/USGS Weekly Volcanic Activity Report, Semeru has exhibited regular eruptive events, with daily ash plumes rising 400–1 200 meters above the summit and drifting in multiple directions in late May 2025. The volcano currently holds Alert Level 2, and the public is advised to stay at least 3 km from the summit in all directions, and 8 km to the southeast, due to ongoing lahar, avalanche, and pyroclastic flow hazards.

Semeru is a large stratovolcano and the highest volcano on Java, Indonesia. Hazards at Semeru include frequent ashfall, lava flows, pyroclastic flows, and lahars. Populated areas such as the town of Lumajang, located to the southeast, are situated within areas potentially affected by volcanic phenomena, highlighting the need for ongoing monitoring and adherence to official exclusion zones.