A number of amateur videos filmed by local residents show how the catastrophe unfolded in Mandra, west of Athens, on Wednesday.
At least 15 people were killed, dozens are injured and many are missing following the flooding that was caused by flash floods.
The overnight deluge turned roads into fast-flowing rivers and trapped dozens of people in their homes or cars.
Some residents were forced onto rooftops and balconies while cars were thrust onto porches or tipped onto their side.
“This is a biblical disaster,” Mandra Mayor Yianna Krikouki told state broadcaster ERT. “Everything is gone.”