A volcano in Indonesia is erupting for the second day in a row after 400 years of being dormant.

About 30,000 people evacuated the area after Mount Sinabung began spewing hot ash and smoke more than a mile into the air over the weekend.

Officials have placed the area on the highest possible alert.

The Indonesian government has set up public kitchens for refugees, and more food, tents and medicine are on the way.

Experts said they're not sure what the volcano will do next.

"We don't know what set it off, how long it will continue or whether we should expect pyroclastic flows or more powerful eruptions," one local government vulcanologist said.

Indonesia sits on what's called the "Ring of Fire," an arc of volcanos and fault lines. Experts said there are 129 active volcanoes in Indonesia.