REUTERS/Tarmizy Harva
Mt. Sinabung, an 8,350-foot active volcano, last erupted in August 2010. This eruption began Sunday. More than 15,000 residents have fled the area, according to the AP.
A general manager for air navigation at Kuala Namu airport in Medan, the capital of North Sumatra, told the AP the
Ash can build up in the machinery of a plane, jam the engines and cause them to fail, according to The Guardian. The 2010 eruption of Eyjafjallajökull in Iceland forced authorities to shut down much of European airspace for about three weeks, according to Icelandair.
Here's a map showing Mt Sinabung's location:
Google Maps Screenshot