T

he disaster mitigation agency in Karo, North Sumatra, sent out a warning to residents around Mount Sinabung on Tuesday alerting them to the impending risk of lahar — a type of mudflow or debris typically composed of a slurry of pyroclastic material, rocky debris and water that flows down from a volcano, typically along a river valley — after a child was killed on Monday in a similar incident.

The powerful lahar that occurred on Monday afternoon destroyed several houses in Kuta Mbaru village.

The potential for a further lahar, also known as cold lava flooding, remains likely considering the high intensity of rainfall in the region, said disaster mitigation agency head Matius Sembiring.

In anticipation of further lahar, he said the regency administration would dig a number of small rivers to divert the stream or flood, otherwise it could overflow into residential areas.

“Suitable heavy equipment was deployed to selected tributaries today, including the Bekerah River which remains covered by the rocks and large logs that were dragged down by the lahar [on Monday],” Matius told The Jakarta Post, Tuesday.

The lahar swept through a residential area in Kuta Mbaru village, Tiga Nderket district, Karo, on Monday afternoon, destroying three houses. Five people were dragged down by the debris flow.

Three of the people were saved, but a girl named Raihan, 6, was found dead some 100 meters from her house. A second girl named Riska, 7, remains missing.

“Riska has not yet been found. The search and rescue (SAR) team and locals continue searching for her,” Matius said.

Alfianus Ginting of Sukameriah said that the laha had left residents around Mt. Sinabung restless, adding that residents remained on guard in anticipation of other debris flow.

Residents can not go to their fields to farm because they can not leave their family members at home alone.

“People were traumatised by the lahar that hit their village. They remain on guard over fear of another debris flow,” Alfianus said.

Head of Mt. Sinabung observation post, Armen Putra, called on people living along potential debris flow routes to remain cautious because of the high rainfall across the region.

He said the cold lava flow that swept Kuta Mbaru on Monday afternoon was triggered by the heavy downpours over Karo regency that had been there for the last few days.

Last year, he said, debris flows swept through residential areas in Susuk village, Tiganderket district. A local was found dead, having been dragged by the flow for 1.5 kilometers.

Armen also reminded locals to stay alert over the possible eruption of Mt. Sinabung, as fluctuating activity had been recorded over the last few days.

“There have been eruptions every day. Mt. Sinabung is still dangerous,” said Armen, adding that his office maintained a level 4 alert level for Mt. Sinabung (on a scale of 1-4).