Eleven people are missing after a boat capsized in rough weather off the Mentawai Islands in West Sumatra on Monday. The vessel, carrying 18 people—10 of them local officials—was headed from Sikakap to Tuapejat when it overturned around 11 a.m.

Seven survivors have been rescued, and search efforts are ongoing. Authorities haven’t confirmed the cause, but boat accidents are common in Indonesia due to poor safety standards and unpredictable weather, according to Reuters.