The eruption from Mount Lewotobi Laki-Laki occurred at 17:35 local time (10:35 BST) on Tuesday, sending a massive ash plume more than 11 kilometres into the sky over the island of Flores.
Authorities have established a seven-kilometre exclusion zone around the 1,584-metre-high twin-peaked volcano. Although there were no immediate reports of injuries or damage, officials remain on high alert.
Mount Lewotobi Laki-Laki has shown heightened activity in recent months. In November, multiple eruptions claimed nine lives and displaced thousands of residents. Ash from those eruptions also disrupted air travel.
Muhammad Wafid, head of Indonesia’s geology agency, urged the public to avoid the exclusion zone and warned of possible lahar flows – dangerous mudslides composed of volcanic material – especially in the event of heavy rainfall.
He also advised residents to wear masks to protect against falling ash.
The National Disaster Mitigation Agency reported that at least one nearby village had been evacuated and several others experienced ash fall outside the restricted area.
A spokesperson emphasised the importance of moving to safe zones, noting that volcanic tremors were still being recorded, indicating continued activity.
This latest eruption follows a similar event in May, when the alert level was also raised to its most severe.
Mount Lewotobi Laki-Laki, whose name means “man” in Indonesian, is part of a twin volcano system with the taller and less active Lewotobi Perempuan, meaning “woman.”
