As early as lunchtime there were road sections in north district and presumably in Yongkang, Xinhua and Rende districts that were flooded and unpassable in small cars and scooters, and though I was able to drive through the floods on my motorbike, I couldn't manage it on the scooter.
There was chaos on the roads too as several underpasses had been cordoned off by the police with cars stuck at the bottom.
Wastewater channels in my neighbourhood were about half full (so a likely depth of between four to six meters) with the water moving at great speed.
Tonight I will wash and re-waterproof my old rain jackets as a precaution in case this rain continues all week.
A final thought: did anyone working at the Central Weather Bureau predict this, or was it just another "black swan"? I think a lot of people would have been better off staying at home today rather than going to work or school simply because the danger on the roads is now so much higher than usual. I would not be surprised to find out that today's rainfall has caused a few deaths in Tainan city. It's been extraordinary, and I still have to go out later tonight to pick somebody up from work...