Overview
- The Darwin Volcanic Ash Advisory Centre confirmed ash rising to about 16.5 km (54,000 ft) at 09:20 UTC and issued a Red aviation alert.
- Large pyroclastic density currents traveled through southeastern drainages, primarily the Besuk Kobokan valley, with documented runouts of several kilometers and possibly up to around 15 km.
- Local disaster teams evacuated residents in Lumajang, with the BPBD Rapid Response Team assisting elderly people to reach safer areas.
- Hazard guidance includes a 2.5 km radius around the summit, an 8 km exclusion along Besuk Kobokan, and avoidance of activity within 500 m of riverbanks beyond that distance; other named valleys include Besuk Bang, Besuk Kembar, and Besuk Sat.
- Reports differ on the formal alert level, with some outlets citing the highest Level 4 and an observation-post officer earlier noting Level II, as monitoring indicates the eruption remains ongoing.