Video report by ITV News Senior International Correspondent John Irvine
In the Sigi district, south of Palu, mud and debris has engulfed the landscape after Friday's magnitude 7.5 earthquake made the main access road "flap like a towel".
Houses were swallowed up when the quake caused soil to liquefy, the national rescue agency said.
The disaster has cut the place off to aid convoys with only small motorbikes and scooters getting through.
At least 1,400 people are confirmed to have been killed by the disaster.
But those who survived described "a wave of mud" carrying their homes more than a mile from where it once stood.
ITV News Senior International Correspondent John Irvine visited the site in Sigi where homes and families were washed away
Among those killed were 34 Indonesian students, their bodies were found under a church, buried by the mudslide.
They were among a group of 86 students reported missing from a Bible camp in the Jonooge Church Training Centre.
The whereabouts of the other 52 students are not known.
There are fears some survivors may still be trapped under the rubble of that and other buildings.