KARO, Indonesia — Powerful bursts of hot ash and gravel erupted from a rumbling volcano in western Indonesia early today, sending panicked villagers streaming down the sides of the mountain.

Six new eruptions in the morning sent lava and searing gas tumbling nearly a mile down the slopes of Mount Sinabung in North Sumatra province. Volcanic material spewed as high as 6,500 feet into the air a day after authorities had raised the volcano’s alert status to the highest level.

About 15,000 people have been evacuated from 17 villages in the danger zone 3 miles around the crater, National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho said.

Thick, gray ash covered villages, farms and trees as far as 43 miles away.