Coriolis Effect and the Birmingham floods

The storms in the West Midlands last night made the news. One of the best lightning displays that I've seen in years. A lot of water fell in a short space of time. After the storm, the water was swirling down this drain at the service station. It was going anti-clockwise. They say water should always do this in the northern hemisphere but in reality it also depends on the geometry of the drain hole and on the initial conditions. The best thing that happened was when a passing car sent plane waves across the system. They were then bent round as they hit the sink hole producing an effect like spiral arms on a galaxy. For the definitive Coriolis Effect film, see https://www.youtube.com/watch?v=aDorTBEhEtk