Bromo has been active for some time, but began showing elevated signs of volcanic activity last month, throwing columns of ash up into the atmosphere. (Antara Photo/Zabur Karuru)

Malang, East Java. An increase in volcanic activity at Mount Bromo in East Java left at least 28 villages smothered in ash, but is still not considered severe enough to warrant an evacuation, officials say.

The volcanic ash has damaged crops and forced residents to remain indoors. Bromo has been active for some time, but began showing elevated signs of volcanic activity last month, throwing columns of ash up into the atmosphere.

On Tuesday, it began spewing lava, which was only visible at night due to the thickness of the ash plume.

Officials say they are bracing for a potential evacuation of the more than 30,000 residents living around the volcano. They have already declared a 2.5-kilometer exclusion radius around Bromo’s crater and closed off hiking trails on the nearby Mount Semeru that could be affected by the hot gases and ash from Bromo.

“We have set up signs to help with the evacuation process,” Dwijoko, the head of the local disaster mitigation agency, or BPBD, said on Wednesday.

Ahmad Suban, the head of the Bromo observation post, said the volcano was expected to continue spewing lava for the next two months.