According to Weather.com
Six inches of flowing water can knock a person off their feet.- Water flowing at 7 mph has the equivalent force per unit area as air blowing at EF5 tornado wind speeds.
- Water moving at 25 mph has the pressure equivalent of wind blowing at 790 mph, faster than the speed of sound.
Add to that how low the car is and yea, your car becomes a canoe before you realize what happened.