Mount Slamet's alert zone cut to 2 km amid continued volcanic warnings and extreme weather threats

Indonesia's volcanology agency (PVMBG) reduced the recommended safety radius around Mount Slamet's crater from 3 km to 2 km after monitoring showed volcanic activity remains high but stable. The volcano stays at Level II (Waspada). Thermal drone measurements recorded crater temperatures between 407 °C and 479 °C, and gas emissions continue, prompting warnings about possible ash fall, lahars, hot material ejection and concentrated gas clouds within the new zone.

The meteorological agency (BMKG) also issued a weather outlook for Central Java on 4 June, highlighting the potential for heavy rain, strong winds, lightning and extreme weather in three districts (Banyumas, Wonosobo, Temanggung). High sea waves (up to 4 m) and a 1‑meter tide surge are forecast for the northern and southern coasts, raising flood risks in Pantura towns such as Pekalongan, Batang and Semarang. Authorities advise residents, hikers and coastal communities to remain vigilant and follow safety directives.