Of all the volcanoes stirring across Indonesia this season, Mount Lewotobi Laki-laki has the widest reach — not because it is the largest, but because its towering ash clouds spill into the flight paths that connect Bali to the world. On the island of Flores in East Nusa Tenggara, this twin-peaked volcano has become the one whose eruptions travelers as far away as Australia and Singapore feel directly.
Ash that climbs into the jet stream
Lewotobi Laki-laki — the “male” of a pair of volcanoes, alongside the quieter Lewotobi Perempuan — has repeatedly produced ash columns above 10 kilometers, tall enough to reach cruising altitude for airliners. In its strongest recent eruptions the plume has risen around 11 kilometers and spread into a mushroom cloud visible more than 100 kilometers away. Volcanic ash is abrasive and can melt inside jet engines, so aviation authorities respond to these plumes by closing routes. Past eruptions have cancelled dozens of Bali flights to and from Australia, Singapore, South Korea, and India, stranding tourists during peak season.
A deadly recent history
The volcano is not only an aviation nuisance; it has been lethal. Its major eruption in November 2024 killed several people and forced mass evacuations when ash and volcanic bombs struck villages near the crater. Authorities have at times pushed the danger zone out to 8 kilometers and moved thousands of residents to shelters. Those evacuations, and the ashfall that buries crops and contaminates water, are the human cost behind the flight-cancellation headlines.
What experts are watching
Monitoring at Lewotobi centers on the pattern of explosive eruptions and the height and drift of the ash plume, which the Darwin Volcanic Ash Advisory Center and Indonesia’s VONA notices translate into aviation warnings. Scientists also watch the seismic buildup that precedes big blasts and the accumulation of material on the slopes that can become lahars in the rains. Because a single large explosion can happen with limited warning, the exclusion zone and rapid evacuation planning are the front-line defenses.
What to watch for
For residents of Flores, the signals are the alert level and the exclusion-zone radius; for travelers, the practical indicator is the aviation ash advisory and airline notices for Bali’s Ngurah Rai and regional airports. If you are flying through the region during an active phase, expect the possibility of delays and cancellations at short notice, and check directly with your carrier. Lewotobi Laki-laki is a reminder that a volcano on a remote island can reach across an entire region — and that the safest response, on the ground and in the air, is to heed the official warnings the moment they are issued.
