At 3:28 AM on Sunday, residents in East Jakarta posted the same thing: a thin layer of grey dust on their motorbikes that wasn't there the night before. By sunrise, it had a name  volcanic ash from Mount Anak Krakatau, the young volcano sitting in the Sunda Strait between Java and Sumatra.

At a glance:

• 33+ flights disrupted (some reports cite up to 209) at Soekarno-Hatta International Airport
• Ash plume reached 20,000 ft on the Java side, 50,000 ft toward Sumatra and Banten
• Airport closure extended from 5:30 AM to 9:30 AM local time on September 6, 2026
• Eruptions began the night of September 4, with six recorded overnight
  
  

Anak Krakatau  literally "Child of Krakatoa"  is the volcanic island that emerged from the crater left by the catastrophic 1883 Krakatoa eruption. It began erupting again late on Friday, September 4, 2026, and by Sunday morning, ash had drifted far enough to force Indonesia's busiest airport to shut down. 

 

 

 

 

 

View this post on Instagram

 

 

 

 

 

 

 

 

 

 

 

A post shared by JAKARTA INFO (@jktinfo)

What happened at Soekarno-Hatta Airport?

Indonesia suspended flights at airports in Jakarta and Lampung on Sunday after volcanic ash from Mount Anak Krakatau spread across parts of Java and Sumatra, according to state airport operator InJourney Airports. The shutdown at Soekarno-Hatta was extended until 9:30 a.m. local time after initially being set for 1:30 a.m. to 5:30 a.m. Lampung's Radin Inten II International Airport halted operations until 8 a.m.

The ash disrupted 33 flights on domestic and international routes. International routes hit included Singapore, Hong Kong, Seoul, Doha, Amsterdam, and Kuala 

Lumpur, while domestic flights to Lampung, Denpasar, and Surabaya were also cancelled or diverted, according to social media reports circulating from Indonesian news accounts. Some outlets, including Reuters and Japan Times, reported the figure could be as high as 209 flights once cascading delays are counted. 

How high did the ash go, and where did it land?

Ash was identified as high as 20,000 feet on the Java side of the volcano, and a plume of up to 50,000 feet on the Sumatra side and parts of Banten province, according to Indonesia's meteorological agency, BMKG. That's roughly three times the cruising altitude of a commercial jet.

The dust reached far beyond the volcano itself. Reports placed ash in Sukamakmur, Bogor Barat, and Puncak  popular weekend getaway spots for Jakarta residents  as well as in South Jakarta neighborhoods like Jagakarsa and Cilandak. One resident described being woken by a friend's message warning that Jakarta had entered a "red zone" for ash, then stepping outside to find her car already dusted grey. 

Is there a tsunami risk?

Indonesia's disaster mitigation agency, BNPB, said there was no imminent risk of tsunami from the volcano, an important reassurance given that Anak Krakatau's 2018 eruption triggered a deadly tsunami that killed hundreds. Still, officials aren't treating the ashfall lightly.

"The public should remain calm while increasing vigilance," said BNPB spokesperson Berton Panjaitan, who advised residents to wear masks and eye protection, avoid outdoor activity, and cover water sources.

Several schools cancelled Saturday activities after students and residents reported eye irritation from the ash, and fishermen called off their trips. For a city that runs on motorbikes and open-air street food, that's not a small disruption.

What should Jakarta residents do right now?

Health authorities are recommending masks outdoors, closed windows, and avoiding unnecessary travel until BMKG confirms the ash plume has cleared. Given the direction reports describe  moving southeast toward Jakarta and Banten  residents further from the strait may see lighter effects than those in Bogor and South Jakarta.

Flight status changes fast in situations like this. Anyone flying through Soekarno-Hatta or Lampung's Radin Inten II should check directly with their airline before heading to the airport.