Aquaplaning

Worn tyres make the water to be dispersed less effectively. Wide tyres leads to that more water needs to be dispersed to the sides. When water can not be led away efficiently to the sides and the tyres are unable to have enough contact with the road, then that could lead to the tyres (and thus the car) being lifted up to the water surface (as indicated by this illustration) resulting in the car skidding uncontrollably.