What is the legal test for hydroplane?

Both parties referred to the legal principles outlined in Fontaine v. British Columbia (Official Administrator), 1998 CanLII 814 (SCC), [1998] 1 S.C.R. 424. In that case, a car left the roadway resulting in the death of the plaintiff’s husband. There were no witnesses to the accident and no one knew precisely how it happened. Weather had been bad the weekend the plaintiff’s husband and the driver of the vehicle went missing, with heavy rain, washouts and heavy winds. Police investigators testified at trial about a swale in the highway where the vehicle was believed to have left the road. Given the amount of rain, it was believed that rain was likely to have collected in this swale. One officer opined at trial that if the vehicle had driven straight through the water-filled swale, loss of control was unlikely, but if the driver had to suddenly turn the wheel, the vehicle might hydroplane, particularly if it had worn tires. There was some evidence that the two front tires of the vehicles showed “excessive wear”. The officer also testified that certain damage to the tire and rim of the vehicle was consistent with the tire hitting a rock or other solid object on the road.