KINABATANGAN: Deforestation may be the primary cause of the devastating mudslide that occurred here last Saturday, said Universiti Malaysia Sabah geologist Professor Dr Felix Tungkol.
He said there were two major mudslides that resulted in the debris flow that has so far claimed five lives.
"The first one was clogged up, producing a temporary dam that later broke under pressure, causing a second, more potent landslide to occur.
"Such disasters are common here," he said, explaining that excessive clear-cutting of trees to make way for oil palm plantations could result in severely weakened soil in the area.
An aerial survey drone had been deployed by UMS earlier to map out the area's geographical properties.
The survey has also confirmed a possible source of the mudslide as a water catchment found further upstream.
Meanwhile, Deputy Sabah Fire and Rescue Department director Zuraidah Latip said those catchment systems were critical for the local communities as a source of clean water.
"However, due to poor construction standards and heavy logging in the area, in addition to heavy rain, it may have caused the catchment to overflow."
The mudslide on Saturday had resulted in the destruction of a worker's quarters in Tongod and swept away a family of 11 downstream.
Three of the victims survived, while six bodies have been found since today.
The operation, entering the fifth day today, will continue the search for two more missing victims at Sungai Pinangah.