Mount Sinabung erupted again in North Sumatra in early September 2026, temporarily disrupting flights at Kualanamu International Airport (KNO), the main airport serving Medan.
The good news for travelers is that Kualanamu Airport is currently operating normally. However, Indonesian aviation authorities are continuing to monitor volcanic ash because another change in wind direction or ash distribution could affect flights again.
What Happened at Mount Sinabung?
Mount Sinabung in North Sumatra became active again at the beginning of September 2026. On September 2, an eruption produced a volcanic ash cloud reaching approximately 14,000 feet.
According to Indonesia’s Directorate General of Civil Aviation, information from the Darwin Volcanic Ash Advisory Centre indicated that the ash cloud was moving southwest at approximately 5 knots.
Volcanic ash is a serious aviation hazard because its movement can affect flight routes even when an airport itself is not covered by ash.
Were Flights at Kualanamu Airport Cancelled?
Yes. On September 1, a thin layer of volcanic ash was detected in the aircraft parking area at Kualanamu International Airport.
The airport was temporarily closed as a precautionary measure. The disruption resulted in:
- 45 flights cancelled
- 6 flights rescheduled
The airport was subsequently reopened after inspections of the airfield and further assessment of the volcanic ash situation.
The disruption also affected the important air connection between Jakarta and Medan, with thousands of passengers impacted by cancellations and delays.
Is Kualanamu Airport Open Now?
Yes. Kualanamu International Airport is currently operating normally.
The Indonesian Ministry of Transportation reported that monitoring carried out at the airport found no volcanic ash in the airport area. Paper-test monitoring was conducted at Kualanamu between 08:00 and 16:00 local time.
Authorities have therefore allowed normal flight operations to continue.
However, this does not mean that the volcanic risk has disappeared. Aviation authorities are continuing to monitor Mount Sinabung and the movement of volcanic ash.
Can Flights Be Cancelled Again?
Yes. Travelers should understand that the current situation can change quickly.
The Indonesian Directorate General of Civil Aviation has specifically warned that changes in wind direction and speed could alter the movement of volcanic ash and potentially affect flight paths.
Airlines also have the authority to reassess their operations based on actual conditions. This can include:
- changing flight schedules;
- delaying flights;
- cancelling flights;
- making other operational adjustments when necessary for safety.
For that reason, a flight showing as scheduled today should not be treated as a guarantee that conditions will remain unchanged.
What Should Travelers Flying to Medan Do?
1. Check your flight before going to the airport
If you are flying to or from Medan, check your airline’s latest flight status before leaving for Kualanamu Airport.
This is particularly important for flights connecting Medan with Jakarta and other Indonesian destinations, because changes to one flight can affect connecting itineraries.
2. Allow extra time for disruptions
If your itinerary includes a tight connection in Medan, Jakarta or another Indonesian airport, allow additional time where possible.
Volcanic activity can result in delays even when the airport itself remains open.
3. Check your airline’s rebooking policy
If your flight is cancelled or significantly delayed because of volcanic activity, contact your airline regarding rebooking or other available options.
Do not assume that another flight will automatically be arranged if your itinerary includes separate tickets.
4. Monitor the situation if you are travelling in North Sumatra
Travelers heading to Medan, Berastagi, Lake Toba or other parts of North Sumatra should continue checking official updates while the volcano remains active.
The current airport situation is normal, but volcanic ash distribution depends heavily on weather and wind conditions.
Does This Affect Tourists Visiting Medan?
At the moment, there is no general closure of Medan for tourists and Kualanamu Airport remains operational.
The main issue for international visitors is air travel rather than normal sightseeing in the city.
Kualanamu is the main air gateway for Medan and an important entry point for travelers continuing toward destinations such as Lake Toba and Samosir Island.
Because of this, even a temporary airport closure can have a much wider effect on a North Sumatra itinerary.
What About Connecting Flights?
Travelers with connections should pay particular attention to the situation.
A delay or cancellation at Kualanamu can affect onward flights, hotel check-ins, tours and other pre-booked services. This is especially relevant when traveling on separate tickets.
If you have a connection through Medan, check both flights independently and keep some flexibility in your itinerary if possible.
Should You Cancel a Trip to Medan?
Not based on the current airport situation alone.
Kualanamu Airport is operating normally, and authorities have not announced a general suspension of flights because of the latest eruption.
However, Mount Sinabung remains an active volcano and aviation conditions can change. Travelers should therefore monitor their airline and official aviation updates rather than cancelling a trip solely because of the eruption.
Bottom Line for Travelers
Kualanamu International Airport is currently open and operating normally after the latest Mount Sinabung eruption.
The airport was temporarily closed on September 1 after volcanic ash was detected in the aircraft parking area, causing 45 flight cancellations and six rescheduled flights. Subsequent monitoring found no volcanic ash at the airport.
The situation is currently stable, but authorities continue to monitor the volcano and ash movement. Airlines may still change, delay or cancel flights if conditions become unsafe.
If you are flying to or from Medan in the coming days, the safest approach is simple: keep your itinerary, but check your flight status before travelling to the airport.
For more practical information about travelling around Indonesia, see our Indonesia Transport Guide, Indonesia Weather by Month and Indonesia Transport Guide.
Sources
- Directorate General of Civil Aviation / Ministry of Transportation — Kualanamu flight operations and Mount Sinabung volcanic ash monitoring
- ANTARA — Kualanamu flights return to normal after Sinabung eruption
- The Jakarta Post — Sinabung eruption and Kualanamu flight disruption
- Indonesia Travel — Medan and Kualanamu International Airport
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