Lukas Polster knew on Thursday evening that heavy rainfall was predicted in his town of Böheimkirchen in Lower Austria. When he asked his neighbour if they should take their cars out of the garage he shares with the other 24 flats in his building, his neighbour laughed. “It was during the night between Saturday and Sunday that we realised the flood was a serious,” Polster said. “I was looking out of my window and I saw one metre of water right below my flat. I realised I had to get my documents and leave, but my brain stopped working in that moment.” By Sunday morning, parts of the town, which…