Water weighs 62.4 pounds per cubic foot. When a vehicle stalls
in water, the water's momentum is transferred to the car. For
each foot the water rises, 500 pounds of lateral force is
applied to the car. For each foot the water rises up the side of
the car, the car displaces 1,500 pounds of water. In effect, the
car weighs 1,500 pounds less for each foot the water rises. Most
vehicles will float in just 2 feet of water. Source: Tulsa
World, p.A11, 10/6/2009