Can a tank be driven across a river? The answer is that it depends on the thickness of the ice.The formula for estimating how many inches of ice will support a vehicle’s weight is h=4sqrt(P). Where P is the weight of the vehicle in tons. In the case of the Dnieper river, it seems like the most it freezes is 16 inches, which would only allow for a 16 ton vehicle – some some trucks and light infantry fighting vehicles like the BMP, but tanks would not be able to cross safely.