system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does hydroplaning work?
gpt
Generally fluids have to go somewhere when displaced - when you dive into a pool, you have to move all the water that used to be where you dived into. This takes a little bit of time and energy, which is why there's a shock when you break the surface of the water and slow down significantly - you're pushing all the water away.

Your average car tire has treads which are engineered to wick water away from between the tire and the road - when moving at speed on a significantly wet surface, the tires are pushing forward into a surface that has a layer of water on it and they need to wick away the water that goes between the tire and road in order to maintain traction. Some tires do this very well and some do not (slicks).

As soon as the tire is unable to clear the water faster than water goes under the tire, the water pushes the tire off the ground and you lose traction, i.e. hydroplaning. Cars are pretty heavy so you need to be going pretty fast in pretty wet conditions generally for this to happen.