Aquaplaning (aka hydroplaning) by the tyres occurs when a layer of water builds between the rubber tyres of the vehicle and the road surface, leading to the loss of traction and preventing the vehicle from responding to control inputs such as steering, braking or accelerating. If it occurs along all four wheels, the vehicle becomes, in effect, an uncontrolled ski.
Heavy vehicles can cause ruts in roads that when it rains they allow water to build up, this happens because the rut removes the ability for the road to drain water efficiently.
The tyre pressures and the amount of tread you have on your tyres plays a big part in ensuring your tyres clear the water efficiently rather than skiing across the top of it.